Windows 7 64 bit random crashes

So my friend has a computer that has randomly started crashilng lately. it occurs when he is gaming or when he is not gaming. it does not really matter what he is doing. it crashed once when he was trying to put the comp to sleep and it also occured when he was playing league. 

his system specs are as follows. the system is not overclocked at all

 we have tried the following:

reinstalling the video drivers

memtest

remove the video card

also, he recently installed new ram. im on skype with him right now. he is going to try putting the old ram in right now. if anyone has any idea what this is let me know. i myself think that the system has some bad drivers, but he hadnt installed any new software or drivers for a week previous to the crashes happening. it is also worth  noting that it doesnt blue screen, the entire operating system just freezes and will not respond until he restarts the computer. 

So it's not self-rebooting, not the PSU then. Just locks up? Sounds like something's eating up CPU resources. I'd run the task manager on the side and see if you get spikes. If you see a spike, then switch to the processes section and see which thing is using up the most CPU. Try booting into 'Diagnostic Startup' using the msconfig tool and see how that goes. If it runs fine, then there's a software issue somewhere. My guess? Something has either snuck its way in or is otherwise just hogging up cycles.

so he reinstalled his os and lo and behold it is still happening. running linux did help. he ran linux from the disk drive. is it the c drive?

Run memtest with one stick, run it again with the sticks switched out, 3rd time with both. Run Prime95 Blend Test for atleast 12hours minimum, again with 1 stick of mem, 3rd with the stick switched out. Also when you freeze, do you have a buzzing noise in your speakers?

he has ran memtest with 2 sets of memory. both passed and either way it stilll crashed. no noise from speakers, unless the music that is playing starts to loop

if it hasn't been done already, have him reset the bios settings to 'optimized defaults' and then adjust as needed, but only stuff that'll affect booting with his hardware. Unplug/remove all non-essential hardware and see what happens. If nothing goes wrong, then add parts one at a time to see if something triggers it. If the ram really isn't the issue, then I'm wondering what the BSOD says. See if you can get him to record that so we can get the gist of things.

he never got blue screens. and the one he did get got deleted or something. but he figured it out. despite what crystaldiskmark things said, it was his ssd. so yeah

the only thing that Crystal reports is speeds, not health. That's what S.M.A.R.T. apps and scandisk are for, but I'm not sure how well they test SSDs.