Does your computer still have Klez?

If so try this Klez removal tool: http://securityresponse.symantec.com/avcenter/venc/data/w32.klez.removal.tool.html

It’s from Symantec, hopefully you don’t need Norton Antivirus to use it.

I think the first thing Klez does when run is shutdown all processes, this means that if your antivirus definitions are slightly out of date, your antivirus gets terminated. (It apparently also shuts down Nimda and CodeRed :slight_smile: )