The key to cleaning, is booting into Safe Mode With Networking, then running two (2) different cleaners. Here is how you can do it:
(1) First, restart your computer in Safe Mode With Networking (reboot).
Re-boot and hold down your [F8] key while re-booting
(2) Boot into "Safe Mode with Networking"
(3) Download Malwarebytes from
www.malwarebytes.org
(4) Install Malwarebytes
(5) **Still in Safe Mode** Run Malwarebytes until it's finished
(6) On the "Quarantine" tab, delete everything!
(7) Restart your computer into SafeMode With Networking.
THEN:
Download and install the free SuperAntiSpyware.
www.superantispyware.com/download.html
Then, run SuperAntiSpyware. It's free, so you don't have to pay.
Then, tell it to detect everything and clean everything. Then, restart computer.
This should fix it.
EDIT: IF YOU CAN ONLY BOOT IN SAFE MODE, then could mean that your REGISTRY is messed up --- but I'm not sure of that. So, what I would do is download the latest MICROSOFT SECURITY ESSENTIALS.
links:
http://www.malwarebytes.org/
http://www.superantispyware.com/download.html
http://www.microsoft.com/security/portal/Definitions/HowToMSE.aspx
Source: Google search :D