The motherboard on one of my old pc's recently went belly up. With that in mind, I was wondering what my best & least expensive options were. PC is a Compaq Presario 4400US (Prior to merge with HP), with a 1.3 Ghz Intel Celeron processor, 512RAM, CDRW. I've found an OEM (refurbished) motherboard & am astonished at the price of $695.00. What do I need to know in regards to finding a compatible motherboard?