Windows freezing!

Before anything, I want to say that I believe it is a memory problem, but being that the computer is new I figured I would explore other options. I built the computer about 4 months ago and at current, the computer runs for a few hours before freezing. When I run any videos or play music it will freeze after about 10 minutes of play.

The best I can do at pinpointing the origin of the problem is about about a couple of months ago I did something I probably shouldn't have; while browsing the internet I came across a "malicious" website/popup, and because of the way my computer was reacting to this website I felt strongly that it was being infected- so in an attempt to dissallow the "virus" to install itself I did a hard restart. From what I can remember it has being freezing ever since. I know this was a stupid move but my old (and much slower) computer was like one of those ancient Nokia phones that you could slam on the ground over and over and it would be fine, thus I never had a problem doing this.

Should I conclude that the memory has been damaged by this or some other problem with my computer?

I have the mobo/ram/cpu under a 3 year warranty but if I can avoid the process of getting it replaced (purchased on the internet) that would be great.

Any suggestions/tips/advice would be greatly appreciated!