I'm still searching for a solution to my problem as I stated in my previous question (UAC being turned off every time Windows 7 starts (once a day)). Today, a program called SpyHunter found an unknown object on my computer. The name of the file is 1UnHooker.sys and it is located in C:\Windows\System32\Drivers\. It has also a registry entry.

Googling this name did not help much. Is it a rootkit or malware? Should I delete it?