Asus P4T mobo and win2K

Specs (this is a machine a built about 3 years ago):
ASUS P4T socket 423 mobo
Pentium 4 @ 1.5ghz
256 MB RAMBUS
Maxtor 30gig HD and Samsung 9gig HD
Radeon 7200 VIVO graphics
SB Live MP3+ sound
US Robotics 56K fax win int modem
Toshiba DVD
HP 8200 CD burner
Intel network card
Newly updated power source (nice one, cant remember brand)
Win2K w/sp4

Here is the problem:
When I upgraded from P3 to P4 I bought mobo, processor and ram to go in my Antec case. I didn't think to upgrade the power source, but when I powered it up it worked. I've always had little problems with the machine but just figured it was because I built it (not my first, but I'm not a pro). At one point I was using it for work, burning cds, editing video and gaming, so it was working ok.

Little issues started to combine and the performance went down. After a few reformats and clean win2k installs I figured there must be a hardware problem. I dug into the power supply and realized not only was it undersized, but it was the wrong type -- I was only powering the mobo with one harness, not the two required. So I bought a new psu and started over. Well, at this point I have no sound (will not recognize sound card) and no cd burner (also not found when installed). The other devices seem to be working properly.

Does this sound like a mobo problem? How should I proceed?