No power after mobo/cpu upgrage

[cadlewv]

Hello all. Sorry to have to ask yet another question.

I upgraded (old mobo had a problem, not much of an upgrade) my computer today. I replaced an older mobo with an ABIT NF8-V2, replaced the AMD Sempron 2500+ with a Sempron 64 3100+ and added two new sticks of Kingston 3200 512MB DDR ram.

First, this would be the third computer I've put together, so I'm intermediately familiar with all of the workings of building one. But now I've run into a problem I don't know how to even start to solve.

Only the basics are installed for now (RAM, video card, mouse and keyboard). I usually keep it simple until it's back up and running. The problem is that now it won't power on. When I push the power button, the CPU fan spins for a split second, then quits. Same for the two case fans... spin for a split second and quits. When I pushed the power button a few consecutive times, the CPU and case fans stayed on, but the hard drive didn't initialize or run for that matter.

I've taken the mobo back out to make sure there wasn't anything under it (like a post not lined up with a screw hole, lose screws, etc.) so I could rule out something shorting out the board. But that's as far as my knowledge has taken me. So I'm back here again, begging for your kindness.

Please let me know if there's any information I that I have left out that would help solve this problem.

Thanks ahead.

[blue60007]

When you pulled the mobo out, did you leave it out and test it out of the box? Also, you have to have the video card and RAM (maybe I'm misreading, but it sounds like you said you are leaving the RAM & Video card out - also, you'd need the monitor in of course to see anything)

[cadlewv]

Yeah, I see that and have changed it. The only things plugged into the mobo are both 512 sticks of RAM, the video card, mouse, keyboard, and my primary hard drive.

[ammo]

do you have a DMM to test the psu? You might of reached your limit on that 350W

[andper10]

Do all of your fans run through your mobo, or are some of them connected directly to the power supply (molex)? Because if fans directly connected to the ps go off after a second, it is clearly a bad power supply. But if they are all running though the mobo, then it could be a bad mobo, a short circuit, or something else.

[glc]

http://forum.pcmech.com/showthread.php?t=132409

That PSU is plenty good for that rig - unless it just died.

[cadlewv]

Ok, everything is working fine now. However, I am wondering what was causing my system to not power up at first. After shorting out the prongs a couple of times in a row, it came on and has powered my system (full system) since. What could've made it only power up for half a second those few times? Could it be that the capacitors weren't loaded with enough charge to do their jobs? (I have no clue about electrical parts).

Thanks.