Strange MS-DOS Window comes up when browsing ( Virus ) help

Hi.. I have been getting MS-DOS Window when browsing online on Mozilla Firefox and Internet Explorer. This DOS windows just comes on and goes off randomly. It is caused by Trojan horse probably . I have scanned my computer with BitDefender Total Security 2010 and it found 2 Trojans and removed them.
Once again I scanned my PC with Malwarebytes Anti-Malware and it found 21 malware( Trojans,adware,Toolkit) etc. I can’t believe my pc was infected like this.
Now this strange dos windows virus annoying me . Here is the pic of this error
http://imageshack.us/photo/my-images/196/doswindow.png/
Maybe System Restore thing can help . I need your help to get rid of this virus.
Your help would be appreciated.
Answer #1
did u run the virus scanners in safe mode ?
if not go do it now.
Answer #2
looks like leftovers from Mcafee av
the removal tool is listed at step 2 of this page
http://service.mcafee.com/FAQDocument.aspx?id=TS100507
Answer #3
run your AV in safe mode
or use an external/ bootable utility
like Hiren’s Boot CD