A great and free virus-checker program is Anti-Vir, personal edition. I've been running it on all my machines for several years and it has worked flawlessly. Highly recommended!
Anti-vir
Plus you may want to run spybot Search & destroy. I know you said you already ran ad-aware, but I've found each of those programs will miss something the other picked up. Running both covers most problems.
I hope this helps.