MalwareBytes Anti-Malware (aka, MBAM) has been very good for me lately. Start the system in "Safe Mode with Networking", install this and run it to remove the nasties.
That, and hit it with some mix of spybot and adaware if you want. Specifically though, there's a particular nasty app floating around that shows itself as "System Center 2011" or something of the like. It changes your wallpaper saying you've been hacked and pretends to be a legit virus scanner. Malware Bytes is the only thing I've found that detects/cleans it.
I personally always use hijackthis because it lets me check out the tcp/ip stack, ie hooks, and anything in the various auto-run locations in windows to keep malware from loading. If you don't know what you are doing, it's possible you could do more harm than good. The list is shows is EVERYTHING, including ALL good and bad stuff. It's up to you to choose what is malicious and remove only them.
Topic: What are your go-to software tools for virus/malware removal? (Read 773 times)