"Windows Calculator" process running at 100%, virus?

Question

Possible Duplicate:
How do I get rid of malicious spyware, malware, viruses or rootkits from my PC?

Yesterday my gf was browsing one site and clicked one of those tricky and shady ads. After that i noticed her computer was lagging as hell, opened the process administrator and saw "Windows Calculator" using 100% of CPU (no calculator was open, at all, do not recall the exact name of the .exe). I shut it down, computer back to normal and after a couple of minutes, boom, lagging again because the very same process.

Initiated the machine, after few minutes, again, lag. Run AVG antivirus, nothing.

What can this be?

Answer 1

To answer the question "what can this be", we would need to know the file name or some other details. You can try and use Microsoft's Malicious Software Removal Tool (MSRT), which will, if it detects the software in question, tell you the name (and also remove it). The MSKB page is here: http://support.microsoft.com/kb/890830

Answer 2

Well, your best bet here is to do a quick check on a website called Virustotal, which allows you to scan individual files with 45+ AV engines. This should give you a pretty good indication as to whether the file is malicious. By the sounds of it, it could be some form of malware.

If it does turn out to be malware, then there are a variety of different ways to go about removal. I found a guide on the internet from someone who is experienced with removing malware - they work in St. Louis. Website here: mrizos' web page