Hi,
I haven't used Vipre, but you seem to think there may be a bug in it causing this problem.
Probably need to uninstall it rather than just turning it off and see if that solves it.
If not, I would try a System Restore to a point before you had the problem.
System Restore - How to
You may like to post the Vipre website to alert to them to this suspected problem.
I assume you had it on a free trial period.
If you would like to try a different antivirus/malware app., the free Avast Home Edition is very compatible with Vista and well liked by many members of this Forum.
FREE antivirus software for Windows with anti-spyware - avast! Home Edition
Hope that helps
SIW2