I am upgrading my Dell Dimension XPS T500 (PIII). I purchased a ECS P4M800Pro-M MoBo and PD 925 3ghz processor. I currently have CD-R/W, Zip Drive, Floppy Drive and two hard drives (13 & 25 gigs). The new MoBo had a 24 pin connection and the PSU in the Dell has a 20 pin. Should I buy just the adapter or do I need a new PSU and what size. This is my 1st time doing an upgrade. I did not want to spend too much money but I want to do it right.
Buy a new power supply. Dell PSU and motherboard connectors are proprietary. Unless things at Dell have changed, they are not compatible with what we would call "industry standard" parts. You could fry your new motherboard.