I'd have to concur with Cman. Any kind of re-direct means that your system has been compromised. And for the stuff that you can see, like that, there's always a ton of stuff going on that you CAN'T see without a good cleansing. My advice, check all of your running processes. Anything that you don't recognize, kill it manually. If you can't, then restart in safe mode and go from there. Do a manual/visual inspection of the folders and files on your system. Scrub your system with a virus scanner and registry cleaner. You'll be tempted to go cheap on these, but if your machine, data, and possibly identity are important to you, don't hesitate in BUYING the proper tools. After you're sure that your machine is running smoothly, REPLACE YOUR BROWSER. FireFox + the AdBlock and NoScript addons will keep you pretty safe. They're not bulletproof, but they're a hell of a lot better than having nothing in place.
After all of that, it's just a matter of being careful what you allow through the NoScript. BE CAREFUL WHERE YOU CLICK.
Good luck to you.