New MoBo and Proc, now computer won't turn on.

[COKE CAN]

Ok, I'm at work and I don't have much time, so I'll give as much infor as possible.

I bought a Gigabyte motherboard and AMD 64 3500+ 939 processor. My computer worked before hand. I swapped everything out. Now when I push the button on the front it won't turn on. Yes, the power supply is on. I connected the correct wires leading from the front for the LEDs and buttons to the motherboard. After unconnecting and reconnecting, I still get nothing. So I put my old board in and same thing. My old board is an ASUS P4C800, which has a light to show the board has power. That light was on, but the computer won't turn on when I hit the button on the front. I'm lost, I'm sure it's something stupid. I need help!

[oz]

Make sure the motherboard is mounted properly to the chassis. Is it properly grounded? Perhaps it's shorted out somewhere?

If all is good there, I'd recommend rechecking all cable connections yet again. Also make sure all components are properly seated in their sockets, especially CPU, RAM, video card, etc.

This certainly sounds like an electrical connections issue of some type.

[JoeB]

Double check that the mobo is mounted properly and there are no unused mount points causing a short.

Disconnect everything except video card, monitor and one memory dimm. No mouse, keyboard or hard drives. Make sure memory stick and video card are well seated. Double check fan/mobo and video card power connectors are correct. Power up and it should at least get you into Bios.

If not, disconnect power switch connector and try touching (carefully) a screw driver across the pins to see if switch is bad.

If you need to you can remove mobo and lay it on the antistatic wrap it came in, and try the screwdriver on the pins. Hopefully you won't have to go this far

Good Luck!

[IsaacKuo]

Also, read the documentation which came with your motherboard. Often, a new motherboard will be shipped with a jumper that set it in "CMOS reset mode". This prevents draining the onboard CMOS battery, but also prevents the system from booting up.

[LondoJowo]

Does your poswer supply have two power connectors for the motherboard (long one with 20 pins and a short one with 4 pins)? If you don't have the 4 pin connected the processor won't get power.

If you have both power connection hooked it you need to make sure it's not a grounding issue. Take the motherboard out of the case and set it up on the anti-bag it came in. Just install processor, ram, and video card, if it boots then it's a grounding issue and you need to make sure nothing is touching the bottom of the motherboard and the standoffs line up correctly. Personally I only have screws/metal standoffs in the 4 corners and use plastic standoffs in the other holes.

[Ethyriel]

All the suggestions are good, except one. It's a bad idea to boot while in contact with an antistatic bag. Antistatic bags are actually slightly conductive, this is how they draw charges away from the PCB to protect them. You probably won't have a problem, but it's not exactly safe. You're best off placing it on the carboard box it came in, or on a wood desk is ok too.

[COKE CAN]

I still get nothing. I did notice neither fan on the power supply is spinning.

[tp671]

Try another power outlet, or plug a lamp or something in the outlet to verify the one your using is working. (sounds silly, but it happens) Your power supply may have given up on you, what brand/type is it? You mentioned upgrading the board and cpu, depending on how far up you upgraded, you may need a new power supply anyway.

[COKE CAN]

Try another power outlet, or plug a lamp or something in the outlet to verify the one your using is working. (sounds silly, but it happens) Your power supply may have given up on you, what brand/type is it? You mentioned upgrading the board and cpu, depending on how far up you upgraded, you may need a new power supply anyway.

Antec 450W, 2-1/2 to 3 years old. The fans on the power supply aren't coming on.

[JoeB]

Your Antec 450W ATX needs a load on output power to operate normally.
This means that you need to plug the power supply to a working motherboard with working video, memory, and processors before the fans will even turn. The only other way to check the PSU itself is to pick up an ATX power supply tester.


You said that you switched all the old hardware back in and had the same problem? hmmm