As I finished up for the night tonight, all of sudden my PC screen went black and then came back up with firefox running in a old style screen and my bottom W7 task bar was a blueish white as if my screen settings reverted to a older display and plus my PC began to get slow with my PC fan speeding up.
I figure 'shit a viruses!' but I ran MSE and antimalwre checker but nothing came up. And half way into the viruses scan everything went back to normal.
Maybe your video card or CPU over heated since fans don't randomly speed up for no reason if your fan is running cool. You might want to install an extra fan to cool your computer better.
