Random blue screens

For the past few weeks Ive been getting many blue screens that pop up just whenever the hell they want to. The blue screen never has the same error message either. Recently its been "INTERRUPT_EXCEPTION_NOT_HANDLED", "IRQL_NOT_LESS_OR_EQUAL", and sometimes there isnt even an error message. Its just the "A problem has occurred..." message. How the hell do I troubleshoot something like this?

Reinstall Windows.

Check for:
 - cpu overheating
 - excessive dust in case
 - power supply problems
 - faulty hard drives or expansion cards

Get a real OS.

>>3
CPU runs at room temp, hardly any dust in the case, and I doubt that its the power supply or any cards since it does this when im idling.

Could just be software errors, of course. Write down the error it gives you and then look at the corresponding kernel code... OH WAIT

You probably need to download and install www.opera.com as it doesnt interrupt your web browsing and it handles exceptions much better than other leading web browsers but uses half the RAM

>>7
virus.

To actually answer your question, best thing to do to troubleshoot it is this:

 - Eliminate any variables you can.  Uninstall everything not absolutely necessary.  Run a virus check/spyware check.  Get ProcessExplorerNT and be sure you can account for everything running.  Get Autoruns and be sure you can likewise account for everything that runs during startup.
 - Get a live Linux CD and do a few kernel compilations.  This is the best way to test your RAM.
 - Check the Event Viewer for information on what was happening right before the crash.
 - Remove hardware components one by one to see if that makes a difference.
 - >>2-8