DLL is an acronym for dynamic link library. A DLL is a library, or collection of files, that contains executable functions or data needed to run the application it is associated with. DLL files usually end with the .dll, .exe., .drv, or .fon extensions. The application links to the file as needed, or dynamically, to use the functions or data in the file.

Often DLLs are linked to multiple applications or can be used by various applications on your computer. These types of DLLs are called shared DLLs or shared components. Many of the DLLs provided by Microsoft are shared DLLs and can be found in the Common Files or the Windows System folders.

If during installation a needed DLL file is missing or inaccessible, an error may occur that prevents the application from being installed. To complete the installation, the missing DLL file must be provided. Some DLLs are provided by Microsoft with the Windows operating system. Other DLLs are written for a particular application and are loaded with the application. If the DLL is one provided with the standard Windows operating system, it can be restored to your hard disk from the Windows installation disk. If the DLL was created specifically for that application, the software vendor needs to provide the missing DLL.

Search Common Errors for the most common installation errors associated with missing or inaccessible DLLs.

Ikernel is InstallShield's proprietary installation engine. Ikernel exists on your computer to drive the installation. An installation created with InstallShield first attempts to install or update (if an older version of ikernel already exists) the ikernel engine files. After ikernel is successfully installed, the rest of the installation continues installing all of the application files.

The InstallShield Wizard is a utility that guides you step-by-step through the process of installing software on your computer. When a software vendor uses an InstallShield product to create a software installation, the vendor can choose to add the InstallShield Wizard to the installation. The wizard can provide you with the end user license agreement and summary information, present installation options from which you can choose from, and display the progress of the installation. It is important to note that it is not the InstallShield Wizard, or InstallShield, that created your installation; the maker of the software created the installation. The Installation Wizard is just a tool that helps to make installing software easier.

The registry is a central database used by the Windows operating system to track your personal settings and the software and hardware installed on your computer. When you install an application, installation choices are written to the registry. The registry contains 5 major branches:

• HKEY_CLASSES_ROOT – contains information on file-related behavior including what files are associated with what applications
• HKEY_CURRENT_USER – contains the preferences of the current user
• HKEY_USERS – contains the preferences of each user on the system
• HKEY_LOCAL_MACHINE – contains operating system, hardware, and application settings
• HKEY_CURRENT_CONFIG – contains hardware settings users can modify for different circumstances

Important: Modifications to the Windows registry, if not done correctly, can cause serious problems to a Windows system. Before editing the registry, see How Do I Back Up Registry Keys on My Computer?

Some installation errors require that you edit the registry in order to install your software. Search the Common Errors page if you are having problems installing your software.

An installation, also called a setup, is a program that contains the complete collection of the files required to install an application on a computer system. The primary task of an installaion is to transfer the application files from the source medium (for example, a CD) to your computer. An installation includes all of the application files, as well as setup engines, that can place the application on the system and configure it to operate on a particular operating system and with other devices, such as a printer or monitor. Typically, a setup performs some or all of the following tasks:

• Obtains information from the system
• Obtains information from the user
• Sets up shortcuts and folders
• Updates the Windows registry
• Sets up the application for future modification or uninstallation
• Displays a product information file
• Displays a status bar to show the progress of the file transfer process
• Registers the user
• Terminates the setup and restarts the computer

A developer is a person who creates computer software. Developers that typically use InstallShield products are setup developers. If you’re a setup developer, visit Support Central for answers to questions regarding InstallShield products.

Office 2000 is Microsoft’s suite of productivity software, which includes applications such as Word, Excel, Access, Outlook, and PowerPoint. An Office 2000 component is a singe Office application. In addition to the preceding applications, you can also install less frequently used components, such as the Equation Editor or Microsoft Binder. During the installation of Office, selecting the Custom installation allows you to choose which components of Office 2000 you would like to install. Any item you can choose to install is considered an Office 2000 component.

An installation error may require a particular solution if you have an Office 2000 or an Office 2000 component installed on your computer.

Consumer Central was created for home users of software, also called end users. If you're having trouble installing software on your home computer, this site is for you. Consumer Central has solutions for the most Common Errors encountered during software installation. If you cannot find a solution at Consumer Central, visit the Who to Contact page for information on contacting your software vendor.

Often when you run your installation on your computer, other applications running in the background can interfere with the installation, causing it to error out. Some of the most common things that interfere with an installation on your computer are applications running in the System Tray, processes loaded in the memory, and system services running in the background. These applications can lock system resources, which can cause an installation to throw unwanted error messages. Applications, such as anti-virus software and IntelliMouse software, running in the System Tray are often known to cause installation errors. For more information on closing these applications before running the installation, refer to article Close Applications Running in the Background.

In some cases, installation drivers or other hardware drivers running in memory can also result in an error message. You should close any such processes before running your installation. Detailed information about identifying and closing such processes can be found in the article Detect and End Previously Running Installation Processes.

Another reason your installation may not run is changes to your computer caused by recent updates. For example, updates to your operating system may cause installations created prior to the update to fail. You may want to uninstall any recent updates, install your application, and reinstall the update. WARNING: You should check with the software vendor who created the update to ensure no adverse affects will result from uninstalling the update.

Setup.exe is the "package" used to install an application onto your computer. The primary task of setup.exe is to transfer the application files from the source media, such as a CD, to your computer. Setup.exe installs installation engines, if necessary, and then decompresses the application files and installs them into the appropriate folders. Setup.exe starts the installation and cleans your computer of unnecessary files once the application is installed.

The Windows Installer engine (also called the MSI engine) drives the installation of your application. It is a part of the Windows Installer Service, a technology developed by Microsoft to standardize installations on the Windows platform. Without the Windows Installer engine, installations using the Windows Installer technology cannot be installed. The Windows Installer engine is already installed on Windows XP. For other operating systems, the Windows Installer engine must be installed by the installation or by the home user. Most installations based on the Windows Installer Service automatically install the Windows Installer engine on the computer prior to running the installation. In case of an error or other unexpected behavior, you may need to install the engine manually. For more information, see How Do I Install the Windows Installer Engine on My Computer?

Documentation on how to install your product is usually found on the product packaging, such as the box, CD case insert, or the label on the CD. Software vendors may also provide installation information in a leaflet accompanying a product, a Getting Started guide, or at the beginning of a user's manual.

When having problems installing software, a good place to look for more information is the readme file. Most software vendors include a readme file with their installations. The readme file may contain information on installing the software, including answers to common installation problems. If you are installing software from a CD, you can view the readme file as follows:

1. Double-click My Computer.
2. Double-click the drive that contains the CD.
3. Double-click the readme file.

If you cannot find installation information in any of the above locations or if you have downloaded software from the Internet, visit the software vendor's web site. Software vendors often provide answers to questions in the Support sections of their Web sites. Additionally, check the Web site for any product documentation, Help files, release notes, or a readme.txt file. Answers to installation questions can also be found in Frequently Asked Questions or a company's online Knowledge Base.

If installation documentation is not included with your product, contact your vendor.

A shared file is a file that can be used by more than one application. The Windows operating system provides a number of shared files that can be used by any application installed. Software developers can also create shared files for their own applications. Shared files allow for the creation of more efficient applications and save time because the same code does not have to be created for each application. It is created once and used by many applications.

During installation, files identified as shared are registered in the Windows registry. Each time the shared file is installed, the registry increments the registry value associated with it. This registry value is also known as the ref count or the shared reference count. So if two applications install the same shared file, the registry value (ref count) is 2. During uninstallation, a shared file's registry value is decremented. When the registry value reaches 0, you will receive a message asking if you want to remove the shared file, which means there is no application using the shared file. In almost all cases, you can click Yes and remove the shared file. The shared file is permanently deleted, and the hard disk space freed. If you choose No, it will not harm your computer. If you are unsure whether or not to remove the shared file, click No.

Your software vendor is the person or company that created the software you are trying to install. Your software vendor used an InstallShield product to create the installation for the software you purchased. If you cannot find a solution at Consumer Central for the installation problem you are having, visit the Who to Contact page for information on contacting your software vendor.