irql_not_less_or_equal BSOD and ntoskrnl.exe are similar error and most likely caused by Realtek HiDefinition Audio drivers.
Error situation may be:
This file is the core of the operating system and usually show us that the error is pretty severe...
Its root cause is varies have you try all the way below:
Boot your PC in Safe Mode
Check your Memory and Hardware
Do Refresh or Restore your PC
Repair your registry to fix corrupted files
Perform disk checking for errors
Run a full system scan
Clean Windows install
If not, I recommend you...