Your computer is probably compromised. Not sure what you can do to get your money back.

Burn yourself a live CD (like ubuntu) and change your password from that. Then you'll probably want to backup your files (non executable only), reformat and reinstall your main OS. REFORMAT, DON'T JUST REINSTALL WINDOWS THAT MIGHT LEAVE FILES THAT COULD REINFECT YOU.
I'd recommend using a sandbox program for running downloaded files and your web browser. Sandboxie is my favorite and, last I checked, the most secure. It has a 30 day trail, but when it expires there's just a 5 sec nag screen and you still get full protection. There's also browser plugins that can help prevent you being hacked as well. Firefox with NoScript is a great start. Request Policy is another great one. Only allow sites you really trust, never allow things you just clicked on off of google. Also it's smart not to just google for porn or "free" downloads, find a few well established sites and stick to them.