I find that most of the time that's a sign of a malware infection or the owner was using registry cleaners or deleting files instead of uninstalling. It's also possible some other app conflicted.
The story is light but let's begin with Grif's advice to scan and remove common malware.
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Using Windows 7, Error code appeared during trial version avg anti-virus uninstall and stated that operation was unsuccessful. Tried repeatedly but computer will not even start the uninstall process. While trying to download new 2011 free avg, the application exe file appears to save ok but will not show up on desktop or anyother location for me to access. Tried other software applications from cnet and got same results. Also restore operation did not work.