I get BSODs after the computer runs for anywhere from a minute to a couple of hours. I have had the problem for some days now, and it has become progressively worse. Sometimes, it hangs on the boot screen, and sometimes it BSODs or just reboots before Windows has started.

The BSODs are most often of the kind IRQL_NOT_LESS_OR_EQUAL or DRIVER_IRQL_NOT_LESS_OR_EQUAL (I have not seen any other). Windbg reveals that a different .sys file is responsible every time.

I've run HD Tune and Memtest, both with unremarkable results. A clean install of the video card driver didn't help. A diagnostic/recovery type tool (I don't remember the name) sometimes starts after a BSOD, but it always induces another BSOD. Safety mode (with network) seems to be unaffected (no BSODs), but it did hang once when starting up in safety mode.

What could this possibly be, and what more can I do to diagnose it? Could it be an OS, or driver error when it sometimes hangs on BIOS? How can I find faulty hardware without buying new components and switching them?

The computer is self-built with all new components in February this year. I run Windows 7 Pro.


I checked the temperatures now. In the BIOS menu, the CPU temp. was 25-30C, then in Speedfan it was suddenly 85-90C, so I spent some time remounting the fan and dusting and stuff, but nothing changed. Incidentally, 30C is 86F, can Speedfan be reading it wrong? Can the CPU temperature jump 55 degrees in the minute it takes to boot, and then cool back down in the time it takes to reboot?


HMonitor gives correct readings for CPU temperature, around 30C. Another temperature (CPU2 in HMonitor, AUX in Speedfan) reads in the 50s, but that shouldn't be a problem.

I'm still curious as to what types of problems cause the BIOS/POST sequence to hang. Gonna try malware scan next.


This problem went away on its own. I don't quite know the cause of the problem, but it might have been an improperly mounted cpu fan.


1 Answer 1


This very much sounds like a problem with the power supply. Typically, the BSOD would occur as soon as the graphics card starts using more power, which usually is some time after the Windows desktop shows up. This would also explain why it doesn't happen in safe mode.

Steps to diagnose:

  • Check that the watts from your PSU are sufficient for all the components you installed (even on peak use). A pretty standard PC which is also used for gaming can require more than 460W (especially if you use high-end graphics hardware).
  • You can use a PSU calculator like this one.
  • If the total power required is near or higher than the one from the PSU, you need a more powerful PSU
  • You can borrow a PSU from someone else or temporarily use an old one to test this

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