I said already
This answers your questions.
Although when you can't even boot into safe mode it means you have hardware problems
Run SeaTools to check the integrity of your HDD. SeaTools for DOS and Windows - How to Use - Windows 7 Help Forums
Run following tests
- Short Drive Self Test
- Short generic
- Long generic
If the short generic fails, no need for the long generic.
Do not run SeaTools on an SSD as the results will be invalid.
Disk Check - Windows 7 Help Forums
Run MemTest86+ to analyse your RAM. MemTest86+ - Test RAM - Windows 10 Forums
MemTest86+ needs to be run for at least 8 complete passes
for conclusive results. Set it running before you go to bed and leave it overnight. We're looking for zero
errors here. Even a single error will indicate RAM failure.