I had an old PC that was working. I pulled the hardware out of it and am making a stripped down PC. I have an ABIT KV7A motherboard that I have moved into a new smaller case. I am using the same power supply, harddrive, motherboard, and all other hardware. After I got everything hooked up in the new case, I power it up and it comes on for about 3 seconds (before any video) and then it powers off.

I couldn't find any significant info about ABIT KV7A , but going by similar ABIT mboards made around the same time, it's probably very similar to this except it has the A revision of the same Via northbridge: http://www.tigerdirect.com/applicat... Make absolutely certain you do NOT have a metal mounting post mounted in the case at a place where there is no mounting hole in the mboard ! In that case the mboard can easily be shorted where the errant mounting post is. Of course, make certain all your connections are correct and all connectors are fully seated. Make sure the ram is and all the cards are all the way down in their slots. You could try removing the ram, installing it again. On many mboards, you MUST have a 3 wire fan connected to the 3 pin cpu fan header, otherwise the mboard will shut down within a very short time when no rpm is detected from that header to prevent the cpu from burning out. If you do have a cpu fan connected to that header but you changed it, the bios has built in defaults regarding what rpms it expects - if the new fan spins slower the bios may not detect it's rpm or may detect it as spinning too slow. ATX mboards are always being powered in some places by ATX PSs, even when the computer is not running, as long as the PS is connected to the mboard, the switch on the PS is on, if it has a switch, and the PS is receiving live AC power. You should ALWAYS remove the AC power to the PS whenever you are going to be connecting or disconnecting anything to the mboard when the PS is connected to it, or the to PS itself. The switching PSs used in computers must have at least a minmal load on them when you start them up. If you start them up when they have no load or not enough load on them, they may be damaged. If you did not do that at ANY time, you may have damaged something, including you may have fried the PS itself. E.g. I fried one PS by merely connecting a hard drive to it when it had live AC power (it was already connected to the mboard and other drives - I suspect I fried it's controller chip). Your PS may be fried. They often partially work, fans and hard drives may spin, leds may come on, yet you may get no video and the mboard will not boot all the way. If you have another working PS you could try, try that. This mboard would work fine with a PS that has a (output) capacity of 250 watts or more.

are all the panel wires hooked up properly? i've made that mistake

double check for bent pins on the cpu swolen caps around the cpu and psu failure

"...swolen caps around the cpu...." Could be, but usually the mboard mis-behaves for a while before it stops working altogether if it has that problem. Examine the mboard to see if you have bad capacitors, and/or other findable signs of mboard damage . This was the original bad capacitor problem - has some example pictures. History of why the exploding capacitors and which mboard makers were affected: http://members.datafast.net.au/~dft... What to look for, mboard symptoms, example pictures: http://www.badcaps.net/pages.php?vid=5 Home page that site - what the problem is caused by - he says there are STILL bad capacitors on more recent mboards. http://www.badcaps.net/ Pictures of blown capacitors, other components, power supplies, Athlon cpu's, etc.: http://www.halfdone.com/Personal/Jo...

Thanks for all the info. I had retried reseating all the cards, and memory. The cables were all hooked up OK, and the CPU fan is working fine. I do think I found the problem though, and I do think it is the PS. My current PS has 2 fans and one of them is not spinning. I tried spinning it (unplugged of course) with a screw driver, and it spins, but not freely. I did buy a new 450W supply, but I have to return it, since the 12V lead is too short and will not reach. I will post my update in a couple of days after I get the new PS returned and get another one.

It did turn out to be the PS. I bought a new one, and it powered right up. Thanks.