Windows 10: PC crashed on some days after startup several times

On some days the PC just works fine but on some days it just crashed after a few seconds or minutes after startup like 5 times and then it runs fine for the rest of the day.
Sometimes a get a normal BSOD, sometimes a frozen BSOD or a BSOD that looks corrupted. And sometimes the PC just freezes or turns off.
In some rare cases the PC didn't even want to turn on again after starting it (the screen was just black and its light didn't turn blue).
These are the BSOD errors I got:
KMODE_EXCEPTION_NOT_HANDLED
IRQL_NOT_LESS_OR_EQUAL
DRIVER_IRQL_NOT_LESS_OR_EQUAL (asstahci64.sys)
ATTEMPTED_EXECUTE_OF_NOEXECUTE_MEMORY (FLTMGR.SYS)
SYSTEM_SERVICE_EXCEPTION (Ntfs.sys)
SYSTEM_THREAD_EXCEPTION_NOT_HANDLED (asmtxhci.sys)
REFERENCE_BY_POINTER
PAGE_FAULT_IN_NONPAGED_AREA

:)

 

PC crashes on some days after startup several times


On some days the PC just works fine but on some days it just crashed after a few seconds or minutes after startup like 5 times and then it runs fine for the rest of the day.
Sometimes a get a normal BSOD, sometimes a frozen BSOD or a BSOD that looks corrupted. And sometimes the PC just freezes or turns off.
In some rare cases the PC didn't even want to turn on again after starting it (the screen was just black and its light didn't turn blue).
These are the BSOD errors I got:
KMODE_EXCEPTION_NOT_HANDLED
IRQL_NOT_LESS_OR_EQUAL
DRIVER_IRQL_NOT_LESS_OR_EQUAL (asstahci64.sys)
ATTEMPTED_EXECUTE_OF_NOEXECUTE_MEMORY (FLTMGR.SYS)
SYSTEM_SERVICE_EXCEPTION (Ntfs.sys)
SYSTEM_THREAD_EXCEPTION_NOT_HANDLED (asmtxhci.sys)
REFERENCE_BY_POINTER
PAGE_FAULT_IN_NONPAGED_AREA

 

Can't get GPU-Z to start with Windows 8.1 startup

I'm not sure how to do that. Could you list the steps for a noob?

 

all games crash!

I suggest you run rthdribl > http://www.daionet.gr.jp/~masa/archives/rthdribl_1_2.zip
Increase the window size step by step and watch your vga temps permanently.
What happens?
If it crashes, run at stock speeds as suggested before and retry.

P.S.: When your system locks, does the display signal turn off after a time?
Stuttering sound or no sound at all when freezing?
What X1800XT model do you own exactly?