I'm receiving a PFN_LIST_CORRUPT BSOD after a few minutes of using my Dell D600 laptop (running Windows XP). Based on my searches, it seems this is typically related to bad RAM. I haven't had other problems, and nothing has changed on this computer. Could it be that one of the RAM chips has come unseated, or is it just corrupted and I should get a new one?
I can't speak for that error, but there's one way to easily rule it out - run a memory testing application.
Memtest+ does the trick nicely. Download and burn the ISO, boot off it and let it run for 24-48 hours - if it picks up errors, you definitely need new memory. If not, then you can continue troubleshooting with some reasonable evidence that your memory is fine behind you.
You'd be surprised at how many times RAM will become ever-so-slightly unseated. Power off the unit, open it up, and reseat the RAM. If the issue continues, you can at least rule that out, and if it doesn't, it's fixed. :)
As for testing the ram, @Greg Work has a good suggestion, although keep in mind that the test can occasionally fail to detect bad RAM; but overall, it's just Good Enough(tm).