It is a pain in the *ss to get rid of, it has a root kit so go get this first.
Kapersky TDSS Killer 184.108.40.206. It is free and so are any updates, it doesn't run in the background or anything like that, no memory usage. You have to open the program to make it run so get in the habit of running it every few days. Next, go to http://www.malwarebytes.org/
get the free download, it only runs 30 days but it is the only thing that will find the infected files, Windows Security Essentials does not find the problem and doing a restore does no good because the problem is embedded in the rootkit virus. Malwarebytes will still work after 30 days and go get updates but it is limited. I paid the $24.99 and bought the full version because i like the way it finds stuff that Windows and others do not find. Believe me, i had problems with this for a while, if you open task manager and see a exe file with 3 letters, that is your virus running, every time you open a program, it also opens, it looks like a real Windows security warning but it is not, be warned, really a pain in the butt.