It's a pretty cheap 400w model, I have an Asus A8n-E mobo, Athlon 3700+ @ 2.4GHz, 2Gb PC3200 RAM, Radeon HD3870 GPU, Audigy Live soundcard, and the usual other bits & bobs.
Voltages are okay (measured with multimeter), but thats not always an indication that sufficient current is there.
Tried my old Radeon X800 card, but still no luck
A friend is lending me another PSU so I will try that. If not, I'll upgrade the mobo, CPU, RAM and PSU (an excude to go dual core ;-)