With the list of problems you've mentioned, it sounds very strongly as if there's a hardware problem.
The various bluescreens put together indicate a problem with memory corruption - which would tie in with the corrupt files on the hard disk. Memory corruption often affects the hard disk contents due to cacheing.
If you can, strip the system back down to the basics. That means, motherboard,
RAM,
CPU, video card and hard disk(s). You are allowed a keyboard and mouse in addition.
If you have a multimeter, then actually measure the voltages at the
ATX connector, or a hard disk connector. If you don't have a multimeter, consider getting a cheap one!
Can you tell us what your core and
PSU voltages actually are, and how you measured them. It could be that your
PSU has developed a fault.
Áedán