Computer only starts when hot, otherwise it is a pain to turn on, . . .

[jimmy1541]

you have to keep pressing the button and sometimes can't get it on without wigging boards, maybe. Kind of hard to describe since I'm describing it second hand.

But when it's hot it turns on, otherwise when it's cold it seems like it's on but nothing appears on the screen either with a video card or with on-the-motherboard video. I tested the memory and it tested good.

I think it's a power supply or maybe the motherboard?

 

[Matt_E]

Check the pw switch front panel headers connection on the motherboard. See if the computer works by jumping the green and black power supply cables with a paperclip

 

[carnageX]

you have to keep pressing the button and sometimes can't get it on without wigging boards, maybe. Kind of hard to describe since I'm describing it second hand.

But when it's hot it turns on, otherwise when it's cold it seems like it's on but nothing appears on the screen either with a video card or with on-the-motherboard video. I tested the memory and it tested good.

I think it's a power supply or maybe the motherboard?

I'd try a different power supply first.

If you already tried one, or don't have access to one, then I would try removing the motherboard / components from the case to make sure that nothing is shorting out (since you said you had to wiggle things around to get it to work).