First, thanks a lot for your help. You posted so much in this thread! Thanks for your time!
As for my GPU, it's not overclocked, but it's factory overclocked. And as the brand is pretty crappy, I'd be scared to overvolt. Altho, I tried. All I can do is add 100 mV in MSI, so I did that. But I noticed that it adds it and after 10-15 seconds it removes it. Even tho it's set to +100, voltage goes down to default one.
But actually, you gave me a little idea about what can be going wrong. Both YT and WMP aren't really heavy. And when on idle, I got lower Voltage than on Load. So it might just stay like that and not have enough voltage and BSOD. But in games, it just has enough voltage and doesn't have problems. Maybe I should try to force constant voltage. Will see how this works out when I got time to test.
Thanks for posting. I did try all kinds of flash player versions, virus/etc scans are useless imo, because it happened on a clean windows install with nothing on the PC. I reseated cables in the beginning, didn't really work. Haven't really checked Device Manager, but I installed exactly the same drivers, nothing more, nothing less 1 year ago and it was working properly. About GPU, I tried 314 drivers which worked before, also tried 320 and 326 drivers which didn't really made a difference.
Thank you too for posting.
I will take a closer look when I can too. Thanks.
Also, after I OC'd the PC back to 4GHz it's working really good. Didn't get any BSODs and freezes last night. My mouse disappeared 1-2 times, but it appeared again fast enough and didn't really make me big problems. My only problem now is the USB Ports. They seem to be really slow. I have a G27 racing wheel and when I plug it in, it takes some time to get ON and whenever I put anything in those USBs, my (USB) mouse freezes till the thing is completely loaded. For example, my racing wheel needs to get calibrated when I switch it ON. While calibrating, my mouse can't move.
Thank you everyone for your help! Especially M3nta1!
I hope the updated info can lead to an easy solution! Me and my strange PC...