Using MSCONFIG to troubleshoot conflicts in Windows XP is discussed in this article.
In Windows Vista, some background processes can cause issues for other programs and processes. These conflicts can prevent applications such as iTunes and QuickTime Player from working correctly, opening, or even installing. You might be able to resolve these conflicts by disabling some items using the System Configuration Utility (MSCONFIG) in Windows Vista. This utility is not included with Windows 2000.
Important: Disabling third-party System Services and Startup Items can prevent some software or OEM hardware on your computer from working correctly. For example, this can affect the CD/DVD control buttons on portable computers or prevent wireless keyboards and mice from functioning. If you are already using the Selective Startup option in Windows (see step 4 below), you will need to keep track of which items you disable and re-enable so after performing this troubleshooting, you can get your computer back to the way it was. Selecting Normal Startup may enable items that you were not using, and could cause issues.
For more information on this issue, including potential causes, workarounds, and resolutions, see: Apple KB Article HT2292.