I was playing bf3 today and suddenly the monitor froze up, and there was a very loud noise in my headphones. Shortly after this, my clock on Windows started to change randomly. Since then it has happened about 3 times, but some times when it happens, if I am watching a movie or looking at youtube I can still hear sound. This is the first computer I have built, so I don't have a lot of backup hardware I can use, but this build has been running fine for about 6 months.
My specs are:
i5 2500k (OC to 4.2)
8 GB 1600 DDR3 (Gskill Ripjaws)
GTX 560 (Gigabyte, factory overclocked)
1tb 7200rpm Seagate HD
Thermaltake 750W Bronze PSU