In many cases, uninstalling a program fails because a file ending in .isu has been corrupted.
One way to get around the problem is to reinstall the program and reboot. Then, rather than using Windows' Add/Remove utility to uninstall, turn to the uninstall utility provided by the program.
You often can access a program's uninstall utility under Start/Programs and the specific reference to the program you want to uninstall.
You may also want to check the Web site of the program's vendor.
If there is an uninstall problem specific to the program, a suggested fix may be available online. Both Quicken and Adobe have posted suggestions on how to deal with uninstall failures related to their programs.
But the best way to protect yourself against uninstall failures is to arm yourself with a third-party uninstall program.