BSOD is no fun.

This is mostly be way of reinforcing something for myself; after sitting mostly unused for 6 months, I fired up one of the XP laptops (an older Dell D600) only to discover that it was jumping to a Blue Screen Of Death after just a minute or two of operation. The exact error message was complaining of the infamous IRQL_NOT_LESS_OR_EQUAL condition, and the c4 parameter was consistent at 0x80502207 continually. Disabling various hardware, swapping the memory from a different (trouble-free, identical) system, and reseating various connectors had no effect; the problem followed the hard drive into the other laptop as well, which pretty well nailed it down as a software issue.

Since there hadn't been any recent new software installs made (though upgrades may have happened silently), I concluded that the easiest likely path to a fix was using the Repair feature on the Windows install disc; fortunately, I had one of those for this machine. Running it, however, did not completely solve the issue, but it rendered the problem somewhat more tractable. After a bit of headscratching, I uninstalled the known-to-often-be-problematic Adobe Flash plugin, and the problem vanished completely. I don't know if the Flash version present was one of the troublesome recent versions that Firefox immediately warns against if they are detected when the FF installer fetches the update, but that seems likely.

Anyway, now I've got it written down where I can find the note next time. And so can you. I hope it helps.