Easy Mod turns into Nightmare

Hi I have an older system that I see by a few receipts I made in 2004. Been wanting to upgrade it to last awhile longer so when I saw a brand new one from close to that era on sale on Ebay I was happy to snag it for $20 + shp. It is a Enermax 600W Noisetaker Switching Power supply. I got an ATI 3850 and a few sata peripherals (cd-dvd writer & a hd) but decided to just change the psu first. I just assumed it would work so did a sano job (wiring etc) and when it was done pushed the on button and ...nothing. For a week I tried everything with no luck. I decided to pull all the connectors and try the old psu and it fired right up. It occurred to me that maybe the 4 pin mb cable could be involved and sure enough I took off the extension cord (4pin to 4 pin) and plugged on a 8pin too 4 converter and it started right up. The unhappy ending is I never got it to post. It would run (all fans lights etc.) but no video. Error beeps differed but mostly were long. I unplugged everything again and plugged the truepower 480 in with a video card and hd and all was fine again. So I will be taking the Enermax out . Maybe it was to new for my setup..had sata connectors but box said P4 approved. I would like to invest in a modern psu that I could use in a future build but not sure if it would take to my present system until then. Any suggestions on one? Whatever is in the future for me will no doubt have a single card.

Specs on Noisetaker- http://www.pureoverclock.com/article8-3.html



P4 3.00G 800 FSB
Abit IS7
OCZ El DDR PC3500/400mhz 512mb x 2 (dual channel)
Antec TruePower 480
ATI 9800 Pro
Case LL ATX 6099