BAD POOL CALLER when trying to reinstall Windows XP?

[paul d]

I am having trouble with a PC im working on, I have been trying to upgrade the RAM however I think I may have exceeded the amount the motherboard could take, now my PC starts up and keeps restarting itself, I have been advised to try and reinstall XP however when I do that I get a blue screen telling me about a BAD POOL CALLER. I even get this blue screen when I try and recover the XP installation. I have access to another machine so could take the old HDD out of the problem machine and delete some files however I do not know which files to delete. I also have access to a USB HDD enclosure so can do the same thing. Please could some one advise as to the next course of action.
The only PCI card installed was the Modem so I have removed that, I have put in the original stick of RAM however I am still getting the same message and behaviour. This is a real puzzle.