Cleanmgr has generated errors...

I'm running Windows 2000 Professional. I may have been infected by a virus that affected my regedit program.

When I attempt to launch cleanmgr.exe I get a message: cleanmgr has generated errors and will be closed by Windows.

A word on the regedit issue: earlier, when reviewing this problem I learned that I could not open regedit; supposedly the administrator (viz., me) had denied me permission to do this. Following advice received here, I used the DOS prompt to change the extension of regedit from .exe to .com, and it has worked since. I have also created new accounts for my wife and I so that we log in as someone OTHER THAN "Administrator," and I changed the security on regedit so that it can only be launched when logged in as Administrator.