Hi saltyboy and welcome to Seven Forums,
BSOD's are frustrating for everyone and many times difficult to find the cause. The BSOD IRQL_NOT_LESS_OR_EQUAL usually is from a hardware driver, or a hardware conflict. Next time you get the BSOD, look it over carefully. Take a screen shot of it with a digital camera to print out, It is divided into 4 parts. The last section sometimes lists a driver by name that could be causing the problem. If so, uninstall that driver and reinstall the latest driver from the manufacturer web site.
It is probabliy the video card driver. Download the latest video driver for the card you want to use. Then go to the device manager, and locate your present video card, go to properties, and you can uninstall the video driver. Once done, reboot, then install the latest video driver, and see it that fixes your problem.
A more tedious way to possibly ID the culprit, is to write down the memory address in the 4th section of the BSOD, that was involved with the stop error. The in the device manager, of your display adapter, see it that memory address in within the range assigned to the video card driver. Is so you know the that's it.
Hopes that helps.