Hey guys, can someone help me out with these insane stop errors????

I research them and they don't seem to apply or if I attempt the fix I think I'm typing something wrong. Maybe I don't have the right resources to research them. This laptop (Northgate) runs fabulously and starts normally sometimes, then other times I've got these crazy stop errors. I can't attribute them to anything specific execpt driver/hardware compatability problems. But when it starts without errors, what's the deal???

I've gotten so far IRQ_NOT_LESS_OR_EQUAL, MEMORY_MANAGEMENT, PAGE FAULT IN NON PAGED AREA........UNKNOWN HARD ERROR, then the next time it will start/run fine. Unchecked the Automatically Restart option so that I could see all these but I can't really get a grip on what I need to do. Is this all from SP1 and 2 updating? Seemed like her laptop worked fine (although this stupid synaptics touch pad on it has been problems from the start, but we disabled that and she uses a usb mouse instead) not really sure what to tell her.

She gave me the laptop after she took it to a guy who charged her $190 to do little but run a million diagnostics on it then conclude that something is wrong with it and it is cost prohibitive to fix. Ha?????? Never reloaded XP or drivers or anything!!! Grrrrrr!!!!!

I formatted and reloaded XP, drivers and updated with SP2. AVG Pro 7.0 on and Adaware Pro. Except for the stop errors, it runs great. Any ideas??? Where should I go from here? I don't think there is anything wrong with any hardware in it, it runs great when there are no errors, I think its driver/software......any help/suggestions would be great.....thanks!

Sharon