GPU turning off, won't boot

[RuleZzY]

Hey, guys. So I have a really old PC, but it's good for CoD2 and surfing the net so I'm not getting a new one yet.

Specs:

Pentium 4 2.4 ghz
1gb ddr RAM
x1650 pro 512mb AGP
Chieftec PSU 400W
MBO Intel D865PERL

Okay, so the problem is when I start it, it sometimes gets me "Please check signal cable" or it displays MBO screen that says "press f2 to run setup" etc. and then it goes off, like on stand-by, I think that my GPU is turning off somehow. I can sometimes fix it if I open my case and take out the molex cable out of my GPU and then put it back, sometimes it boots up and sometimes it doesn't and here's another thing, I drink water and if I place it on the table too hard, sometimes it would turn my GPU off... I don't get it, is it the PSU? I think we can leave RAM out of the question 'cause nothing happens when I plug that 1gb ram into another RAM socket, I also tried with other RAM cookies, but it's still the same. And any HDD I use with my PC, the MBO will display a message like this one on the boot up screen: "Fixed disk Maxtor (HDD model number here)", it happens with ANY HDD I use. So, is it the motherboard or PSU? Before I had problems with my motherboard, it wouldn't boot up so I got a new PSU from my friend and it still didn't work and I got a MBO from him and then I had problems with HDD freezing/GPU turning off, but now it's just my GPU turning off... I know this is a long post, but please guys, help me, I don't know if I should buy a new PSU because it's maybe the thing about molex connectors or should I buy a new MBO? I'm planning on getting a new PC in a year or so, but now, it's not that urgent.
I think I should mention one thing, when I was changing my motherboard, I didn't know how to connect those thin power, reset and HDD LED cables to my motherboard so I just connected them in a random order and now I need to power my PC on by the button on MY PSU, when I want to turn it off I set it to 0 and when I want to turn it on I set it to 1. Can that cause damage to some parts in my PC? I just didn't have any idea how to connect those things, it's seems very complicated...
When I turn my PC off, I would need to "have fun" with the molex cable again to successfully boot it up.
Any help is appreciated.

Thanks,
Jasmin

 

[badboyrog]

its look like your gpu power connector is loose or bad contact?? i dont know if you have an igp?

 

[RuleZzY]

Still didn't fix this. I think it's a PSU problem, anyone will to help? Please, any reply before I try to buy something new like a PSU will help. Thanks.