Problem with upgrade

[Tom4556]

System:
3700 Athlon 64 (new)
Biostar GeForce 6100-M9 (MB) (new)
1 stick 512 MB Corsair (XMS Series) DDR400
Floppy Drive, LG DVD player, NEC DVD Burner
80 GB Maxtor HD
Turtle Beach Sound Card in PCI 1 slot
Aspire 500 W PSU (new)
onboard video
onboard lan

I just purchased the GeForce 6100-M9 and 3700 Athlon 64. I installed the new MB and processor. Was able to clean install Windows 2000 (with SP4). Operating system appears to be working OK - no hardware conflicts. I have built several computers before, but have not ran into this problem before. Here is the problem. When I shutdown the computer from OS and try to boot with from front panel start button - computer gets no power. I can turn off power on back of power supply and turn power back on and computer will boot in to OS and operate OK. When I turn power off and on from back of power supply power LED light stay on until I push front panel button and LED light goes off (should be other way around). Here is what I have checked and tried:
- Rechecked all connections and made sure MB is installed in case correctly
- Tried system RAM in different sockets as specified in manual. Tried diffrent RAM
- +3.3v, +5.0v, other power levels all appear to be well within 3% tolerance range of new power supply.
- downloaded current drivers and bios for MB from Biostar website.
- I tied disconnecting HDs, DVDs, soundcard, floppy one at a time. Power LED light stays on in front computer panel without computer on. I still can return MB, but not sure this is the problem. Any ideas or suggestions would be greatly appreciated.

[Cricket]

I would return the motherboard for a replacement.

This is just me, but I would replace the Aspire power supply with something better too.

Cricket