You've been struggling with this issue for six days now. Two situations that will definitely eat huge amounts of resources are rootkits and a damaged operating system. By first eliminating the possibility that you're infected you can then safely take the steps to repair your system.
Since rootkits are undetectable by normal AV scans, aren't visible as a Windows process, and can do a large amount of damage to critical system files and registry entries as they rewrite code, I have two suggestions: Kaspersky's anti-rootkit utility;
TDSSKiller will take care of any possible rootkits. On that page click
"1. How to disinfect a compromised system" and you'll find the download link for
tdsskiller.exe. Read all the info on that page so you understand how to use it. When TDSSKiller has finished its work it's time to repair your Windows installation.
The simplest method of completely restoring your system without losing any installed programs, settings, and personal data is by performing
Win7′s no-reformat, nondestructive reinstall. It's simple, but familiarize yourself with the procedure before you begin.