Fake Antivirus
Since beginning of July we started getting many requests to remove rogue anti-spyware and in many cases damage to the system may be reversed. The spread of the AV Security Suit seems to be related to recent vulnerabilities in browser plug-ins flash and reader, and rarely to activity.
The rogue security suit is downloading many encrypted files with random names so the most antivirus software will not detect it, sets itself to multiple auto-run locations, monitors all your internet activity, blocks most tools that could be used to remove it, pops up false infection alerts and in order to remove these completely safe files, it asks you to purchase full version of the software.
On pre-vista windows operating systems, in some cases the damage can be reversed, but on vista and newer OS with standard protection system, in most cases full system functionality can be restored.
Removing AV Security Suit completely can be a challenge even for professionals, that's why most of them will offer you only an easy solution: to remove everything and restore it factory default, but many cases integrated recovery system was damaged, so they may also require you to buy another windows box which is not cheap or install you illegal copy, all though it is possible to keep your current license and save you hundreds of dollars in addition to repair itself.