Try this:
Firstly, boot your computer to the Safe Mode menu screen. You do this by repeatedly pressing F8 as soon as you boot up. Once there, use the arrow keys to highlight Safe Mode with Networking. Continue to boot from there, by pressing Enter. You will now see some drivers being loaded. There will be a pause at some point. This usually lasts for no more than 30 seconds.
If that's successful, download and run TDSSKiller.exe from Kaspersky Lab. It's tiny, and takes just a minute to run. It hunts down and kills a specific family of rootkits:
http://support.kaspersky.com/faq/?qid=208280684
Regardless of the results, download the free version of Malwarebytes' Anti-Malware (MBAM). Install it, get updates and run a full scan (still in Safe Mode). This is a direct download link. Copy and paste it into your browser’s address bar, and press Enter.
http://www.myantispyware.com/mbam
After this, try rebooting normally. If that's successful, I recommend you run another full scan with MBAM. It will detect malware that wasn't running in Safe Mode.
You should now delete TDSSKiller.exe, as updated versions are often made available. Malwarebytes' Anti-Malware can be easily uninstalled, should you wish to do so, but it may prove to be beneficial in the future.
If none of this works...
Try 7-Zip. I use it. It's free.
http://www.filehippo.com/search?q=7+zip
Hope this helps.