Get one of these and make the disk on a known safe computer. Then boot from the just made CD and let it scan.
After that has completed, get Malwarebytes: http://download.cnet.com/Malwarebytes-Anti-Malware/3000-8022_4-10804572.html
Install that and let it complete a full scan. If any problems arise that need addressed or help is needed on any of the results found, please come back.
Okay this is the deal....my grandson was playing games on the computer ( he is 9 ) and when he stuck to the usual games he was fine but he downloaded something from I "think" Gamevance and my desktop is now a MESS! It has a blue patterned screen with some fake warnings and it says it needs to use this so and so program to get rid of virus. I tried to run AVG and Trend Micro and got nowhere. I have a virus free laptop so could make a disc but not sure what to do or how to do it. Any and all help appreciated.