Righto, I've bought some 256mb 144pin sodimm ram for my laptop and I think its 144mhz. The laptop is a Compaq Presario with a 450mhz p3 and has 64mb base memory. I keep getting errors, reading up on the errors it appears its a ram problem. Now how would i go about finding on what sort of ram my laptop needs or is the ram I bought buggered? Main errors include: 'windows/System32/pci.sys corrupted or missing'. and also 'file setupdd.sys could not be loaded. the error code is 4', when reinstalling windows.