TDSSKiller (also known as Kaspersky TDSSKiller) is a free anti-rootkit detector and remover for Microsoft Windows.
It is able to scan certain areas of your computer such as the system memory, services along with drivers, boot sectors, loaded modules (reboot is required if you choose this), use KSN to scan objects and (optionally) it can detect TDLFS file system or verify file digital signatures. It is one of the fastest anti-rootkits tools being able to detect and remove all kind of rootkits (especially those identified as TDSS or Win.32.TDSS ) such as Alureon, Cidox, Cmoser, Sinowal, Whistler, Phanta, SST, Pihar, Stoned, MyBios, Zhaba. It is also capable to detect ZeroAccess rootkits, various bootkits (malware that infects the MBR - Master Boot Record) etc.
Important: If an infection is detected you might have to reboot your computer and you are advised to save opened documents before scanning your computer.