My friend's parents bought a custom computer off of Craigslist for $175 and quite frankly... it sucks. 3 times since last year I've had to fix it for them (because they aren't taking chances with Funky Monkey). At first I thought it was the power supply, which is a 250W Hi-Pro, but I noticed something else. The motherboard, a PCCHIPS P23G, has two memory controllers, one for DDR and one for DDR2. When I'd swap out the couple sticks of DDR in it already, it wouldn't post. Once I put in a stick of DDR2 of my own, it'd POST and would still POST after I put back in the DDR.
Anyways, I've decided to just put a new board in it and it seems to be working fine for now, but before I charge the parents $50 for it is there absolutely any other possibility as to why the first mainboard would do what it does?
Other specifications:
Celeron D 3.33GHz
40GB Western Digital Caviar
Samsung CDRW
XKROMA ATX case
Windows XP Pro
The new mainboard is a Jetway P4M9MP