If you believe the problem started after a recent s/w install, then uninstall that same pgm. Then check results, if it appears to work OK, then you found a bad pgm. or some incompatible feature or setting. If you're running XP, try using the "restore mode" to return to a date when things were running all right, same for WinMe.
If none of this works, then at least scan your system using the latest AV update and/or use some spyware scanner as well. You can't leave any of this to chance, so scan for some malware at fault before any restoring or doing the above.

enjoy Happy -----Willy