Smulet Back

Sorry for using this type of problem, but I couldn't find one that fit my actual problem. The problem is that , since I came back to Second Life my COMPUTER is freezing then crashing after I log into Second Life. I have tried a variety of third party viewers and also the one from Linden Labs. I log in and everything is completely normal, everything runs fine, FPS look good, graphics too. But after few minutes, around 7 minutes, it feezes afterwards my computer 'blue screens' and crashes After that I need to reboot it. It's the first time it happens to me in the entire time I have had my computer. It is capable of running Second Life with no problems, but I don't know what is happening. I have tried clearing cashe, and various other methods. Can you please help me? Thanks in advance. System: RAM: 6GB Hardisk: 500GB Graphic Card: AMD Radeon HD 6550D OS: Microsoft Windows 7 Ultimate Edition (build 7600), 64-bit Cable Internet Connection