Hello and welcome. This is a nasty one.
Backdoor:Win32/Rustock is a rootkit-enabled proxy trojan used to send large volumes of spam from infected computers. The trojan consists of a user mode installer and a kernel mode rootkit driver. The rootkit driver hides registry keys, files, TCP ports and memory objects and also hides itself from applications containing the following strings: RootkitReveller, BlackLight, Rkdetector, Gmer, Endoscope, DarkSpy, Anti-rootkit.
The only way to get this is with a deeper look. Please follow this Preparation Guide
and post in a new topic.
Let me know if all went well.