Windows 7: random BSODs and lock ups while browsing, using utorrent etc.

So this started after a fresh install of windows 7 and a bios flash. I've tried flashing again but unless I missed some important option, then I'm pretty sure it's not the bios.

These random freezes and BSODs occurs when I'm booting, browsing, watching something in VLC, and happens REALLY often while using utorrent, but playing HoN works just fine and so does the computer while I just let it idle.

I have tried updating all the drivers but the BSODs seems to be cause by so many different drivers, so I guess this Is a hardware problem
I tested the memory using memtest86+ with no errors for 12+ hours,
I've tried switching out my graphic card, sound card, network adapter and hard drive (that's all the spare parts I got).

So can you tell if this is a hardware or software problem?
If its a hardware if it's the mobo or psu?
Also note that I'm a newbie so I might have missed some important bios option,
but I've tried using "Optimal" and "Failsafe" defualt values.