PC Keeps Blue Screening / Hardware Or Software?

My computer has been Blue Screening a lot recently making it basically unusable.Here are the stop codes within the last 24hrs. I also took a photo of the screen so you can read the full message:
***STOP: 0x000000F4 {0x00000003, 0x88CBB790, 0x88CBB904, 0x805011F8}
***STOP: 0x0000007A {0xC05D35E8, 0xC000009D, 0xBA6BD2A0, 0x3C3D2860}
Every time it is different, sometimes the error is just along the lines of Unknown Hard Error. The BSOD seem to happen at any time; before Windows boots up, in Safe Mode, or in Windows whilst doing nothing or using software etc. Though it usually happens in spells i.e. several crashes in quick succession then reboot and it can be fine for a few hours. During this stable time .Ive tried to get it to crash on purpose by loading up lots of programs to try and strain the system, but it seems fine. I thought it might have been the hard drives, but after using a program called HDD Regenerator to check for errors it found 0 bad sectors. I have also tried reinstalling all the Windows system files from a partition on the hard drive set up by the manufacturer (MESH Computers), and running several Scandisks, which seemed to fix the problem for a while. Ive also done all the usual spyware and virus scans.

This morning while trying to boot into safe mode I got an error saying Windows could not start.Does it sound like a hardware or software error? I had to replace the chipset fan on my motherboard a few months ago and Im wondering if it overheated and some permanent damage was done? Formatting the hard drives is really last resort for me.