boot on power-up

Hi,

I'm trying to accomplish what I thought was an extremely simple task, of putting a capacitor across the atx power switch so it will turn on as soon as power is applied (as the bios does not have this feature).

I do NOT want a 555 circuit or any kind of circuit at all.. just a single capacitor and maybe a resistor to drain it..

I tried 3 different caps as follows:

1. 0.01 uF ceramic - does nothing

1. 0.47 uF greencap - does nothing

2. 10 uF electrolytic - will work the first time power is applied, but nothing after that untill I drain it (remove and short the leads for a few seconds).

What value capacitor should I use ? Do I need a resitor across it to drain it quickly when power is lost ?

I thought it would be a simple thing and the value wasn't important (ie. I could use any reasonable value).

Regards, Chris