Computer permanently freezes, requiring hard reboot

Still organizing my stuffs and prepping for the memtest >.< Hopefully I'll have more information later this week.

About the GPU overheating... that might be a possibility, but I just had my computer freeze with a 40 C GPU. No idea about the CPU, but the air wasn't blazing hot or anything. Also, does an overheating GPU really cause the sound to cut off instantly?

40 C for a GPU is nothing, those things can get up to 70 C or 80 C without any problem. So that 's not it. It can be the memory though. Both system RAM and video RAM.

But if nothing feels like overheating (you notice this quite quickly when you open the case and move your hand around), it's most likely malfunctioning memory. It's quite common for PC memory to stop working top notch after +/- 2 year of extensive use. Most people won't notice it since Windows 7 most of the time corrects these errors itself (old windows version showed the blue screen thingy when this happened).

The only way you can really test it is swap these parts with other ones and see if the problem is still there. Just remember to only swap one part at a time, not all at once.

But then again, it can also be another part of the PC that's malfunctioning (unstable PSU voltages under high load, wrong BIOS settings, etc), but again, freezes are most often related to memory issues.

And about the sound, if the PC freezes, so will the sound.