Good tip for anyone wanting to test out a website that they suspect might contain malware, viruses or any of that other stuff that plagues Windows users - Download TAILS (The Amnesiac Incognito Live System) and burn it to a disc and boot up the PC with that. Then you can browse the web in complete safety as the system runs entirely in RAM and from the disc, and never writes anything to the hard drive, so doesn't leave a trace on your PC. (just remember that anything you save / download from the site will be stored in RAM so if you want to keep it you'll need to copy it to a USB flash drive or something before you switch off or reboot)
https://tails.boum.org/
The latest version is 1.7 which fixes a few bugs in the previous release.
By default, Tails will browse the web using TOR to protect your privacy by keeping you anonymous but you can also use the regular internet with it if you're only interested in keeping malware at bay. This is done by using the so-called "unsafe browser" (which is perfectly safe but not anonymous)
Alternatively, use Linux rather than Windows, as 99.9% of the malware won't work in Linux (beware of some browser hijacks and javascript shenanigans though as these can be cross-platform, even infecting Mac users)
Tails is pretty much completely invulnerable as it's a fresh install every time you boot it up. I suppose it MIGHT be possible for a cleverly-scripted piece of malware to break out of the Tails sandbox and infect the main hard drive but to be honest I've never heard of this happening. For the ultimate in safety, take out your hard drive and run Tails off the DVD disc, though you'd have to be seriously paranoid to go to those lengths, though if you spend all day checking out slightly dubious websites, get a laptop without a hard drive and leave the Tails disc in the optical drive.
Oh yeah and since Tails uses TOR, it's great for watching those Youtube videos that are not normally available in your country (though this will be more relevant to european users than US ones)
Using TOR is slower than regular internet though. Not usually an issue but something to bear in mind. Probably crap for online gaming...