Make sure you get the 340watt power supply and not the 300watt. I bought one with the 300watt power supply and it would power up the motherboard but it would not post, no beeps, nothing. Others have also had this problem with the Enlight 300watt power supply.
The funny thing is I had an old 250watt enlight power supply and it worked no problem.
I have the Shuttle A31(kt266a) mb, 512 DDR crucial memory and Athlonxp 1600+.
I bought all my stuff from newegg and didn't have any problems.