I saw a report about this alond the lines of conflicts especially with virus checkers although the message appears in application programs. Before doing anything too drastic try the following steps.
1) close your virus checker. (especially likely with Mcafee or Norton)d
2) completely delete it from your system using your uninstall.
3)restart your computer
3) reinstall windows. (I am using XP where this problem occurs)
4) reinstall applications that have been having problems
5) Restart computer
6) reinstall virus checker
7) restart computer
I was having problems with Free Office and Easy Office which the above approach solved.