My desktop shows some of the signs of an ActiveX or virus attack: Google searches redirect, IExplore processes run in the background even when I close the program and force it to end process. I've upgraded to ZoneAlarm Extreme Security, but when I try to Enable Virtualization, the process never completes. The computer is constantly freezing, I've lost my desktop settings and I've disconnected my modem as I was terrified to think what it might be trying to do.
I'm posting this from my work pc.
I've only got basic knowledge of computers and programming and would appreciate any advice.

Operating System:Windows XP Home Edition
Product Name:ZoneAlarm Extreme Security