Hi. A few days ago I finished installing a g-force 4 (64 mb) video card. I reached over to press the power button but my computer didn't power up. I unplugged everything, plugged it back in and then it turned on. But just as windows was loading it shut off again. This went on for a few more minutes when I decided to open up my computer to check things out. My best guess was that something was wrong with the power and that the newly installed graphics card might have overloaded my computer's power supply. So I took the card out and my computer still failed to power up. I played with the switch on the back of the PSU (an L&C 300atx)and noticed that it would only turn on sometimes (rarely) thereafter. And I knew this because whenever the PSU actually worked I heard a faint, high-pitched noise coming from it. When I heard this, the computer started up, only to shut off again from 15 seconds to 3 minutes after. So I bought a new PSU (a atx p4-12v 300w). When I installed it properly, my computer wouldn't boot up when I tried to turn it on. Upon reinstalling my old PSU, and after waiting for some time the computer turned on for about 15 seconds. I just finished reading an article saying that if a high-pitched noise can be heard from the PSU then it's done for. I also read that other components from my computer could have also been damaged from long term power supply from an old PSU. Does anyone know why my old PSU will work RARELY and my new one not at all?? I hope nothing on my motherboard is damaged! Any help/suggestions would be GREATLY appreciated. Even if you're not sure, I'd like to hear just that. Thank you very much for reading this! (i tried looking at the other posts for answers, but with no luck)

I assume everything had been working fine before you installed the GF4? What was your old card? Did you try putting it back in & seeing if it would boot? Did you check all connections & reseat all you cards? Maybe you bumped something while removing your old card & installing the new one....

Hmmmmmmm, Bit of a stick situation really, i had similar problems. The best way to look at this is to see what "ISNT" wrong. First of all you know that the power cable hasn't blown a fuse. Secondly, i dont think anything inside your machine is damaged, i believe there are many safety features to ensure zero OVERLOADS. Some other things to consider are certain fuses in certain power plugs. If for example your using a 13Amp fuse in a 10Amp machine, your gonna be disturbing things in the PSU. When My PSU made the high pitched sound, it sure as hell had died. I know your PC comes on for a few seconds and all but you know, sounds a little iffy. ANother thing it may be of course is the CPU....... perhaps thats old/faulty or even To warm!? Tell me, can you get into the BIOS? i mean without it shutting down? Please ask away if it'll help, ill be here ALLL day, Good luck.

============================================================= I've had similar experiences that have happened under two conditions. 1) You may need to have a higher watt power supply. When you tried to replace the old power supply with a new one, you got the same wattage PSU. Try a 350-400W PSU. 2) There are actually about 5 different specification on the output lines for atx power supplies. Make sure that ALL wires that lead to the mother boards power connector from the power supply are IDENTICLE in color and position on the connector. If not then you are in potential danger of damaging the mother board/CPU etc.... borelli34

I didn't really have an old video card I don't think...I had my video integrated on to the motherboard (an SIS something). After pining for hours on how to find a way to disable it, to install the new one, I couldn't find a way so I just stuck in the new video card. And it did work when I had 3 precious minutes to try it out before my computer crapped out on me. Could that have done something? I checked all my connections and tried taking out my card, but no results. The thing is, when my computer DOES turn on with the old PSU, either the red LED by the power switch goes on and the green one goes off or nothing at all. Which I think is telling me something. When the green light goes and stays on (which is very very rarely) my computer boots up and loads windows. Most of the time I get a red LED or no LED at all, and although the computer turns on nothing else happens. Hopefully nothing's wrong with the CPU. I don't think I need a higher wattage. I have a DVD ROM and CD RW, the new video card, a hard drive, floppy drive, and 256mb RAM. And of course the athlon. Well, maybe I do; I heard that 300w only puts out like 280w or something. I am more inclined to the idea of the wiring from the power supply to the motherboard. Some of them ARE different colors and, by judging from the specs on the sides of each of the PSU's the wires are putting out different amounts of power. Should I take my PSU back and use my old one to aid in finding a new, more identical one (possibly with more wattage)?