For most of today's computers, 250 Watts doesn't cut it anymore. Also, as power supplies age, their output tends to decrease gradually. To troubleshoot this problem, I would suggest 2 possible solutions.
 
First, disconnect the power cord from your PC for about 10 minutes. Then, plug your PC back in, but make certain it is plugged directly into the wall - no surge protector (just for testing). If the computer powers up ok, then shut it down and include the surge protector. If it still powers up ok, it needed a power cycle, and should work fine for a while longer.
 
The second suggestion would be for you to go to a big box store like Best Buy and buy a new ATX power supply (300 Watts or greater) and replace your old one with the new one. f it works, problem solved. If it doesn't, then return the power supply to the box store and tell them you needed an AT power supply and this one wouldn't work for what you needed.
 
No matter how you get your system working again, you might consider using a Power Supply Calculator to determine how much wattage your system really needs before you buy a new supply.

Ok here is what is happening now. I went and bought a 350 watt PSU and hooked it up and it booted just fine. I had my PC on for probably an hour or two at the most, and this morning it wouldnt boot again. (With the new 350 watt PSU) I unpluggd for awhile and plugged it back in and it booted up. But when I turned it off it wouldnt boot up for another 15 minutes or so. The power supply calculator recommends a 261 watt PSU. So 350 should be plenty. I am just confused why it is doing the same thing with a new PSU all of a sudden, and it never even did this before with the 250 watt one.

System specs would be nice, for all we know, you have a Commodore64......

Sorry I had them in my original post, but i was typing on my friends tiny Mac laptop (yuck) and kept hitting the back key and losing my post! Here we are:
 
Celeron 2.8 GHZ (Stock fan/heatsink)
Nvidia Geforce MX4000 128mb PCI video card
1 GB SuperTalent PC2700 RAM
120GB 7200RPM WD HDD
2 80mm case fans
1 8" cold cathode light (not plugged in for this testing)
Intel 845GV motherboard
Lite-On 48x CD-RW
Lite-On 56x CD-ROM
And the powersupplies in question.
 
Here is another piece of confusing information. After running normally on the 250 watt psu, when it wouldnt start, I unplugged everything I didn't need to boot up and it still wouldnt work, but after awhile I plugged everything back in except I didn't flip the switch to the cold cathode light on the back of the pci slot, and usually i can turn it on and off while the pc is running, but this time i turned it on and the pc shut down.
 

Originally posted by Relic:

Quote:System specs would be nice, for all we know, you have a Commodore64......  
Hey now, let's not mock my still working C64 box
 
 
@Tool, try this out and see if you can narrow down the possible issue:
 
Disconnect the power from the power supply to everything except the motherboard.
 
Remove all expansion cards, this includes that PCI graphics card and anything like a modem, nic, etc...
 
Now, it looked like you gave a total of 1GB of ram, if so, how many sticks ?!? If more then one, remove all but one stick.
 
Now then, you should have only the motherboard, cpu/heatsink fan connected.
 
Does you motherboard have a standby led on it ?!? If so does it light when you plug the ac power into the power supply ?!?
 
If not, then perhaps there is a fault on the motherboard, could be the voltage regulation circuitry is flaking out.
 
The only way to verify this would be to test out your parts on another motherboard and see what happens.

jimmijo
 
Heh heh heh, I just got my new system, upgrade from a 1.26 Tualatin/6600GT AGP, 512mb RAM, to a DFI LanParty Ultra-D, 1GB(2X512) OCZ Dual Channel Platinum EL 2/3/5/2, eVGA 7600GT CO, AMD Athlon64 3700+.
 
My very first systen was a "Patriot Computers Canada"(now bankrupt) with a PII 266(@356 using H.Oda's SoftFSB), Matrox Mystique PCI, 64 major megs of RAM.
 
I started out on my bro's Tandy(Radio Shack) 386SX. Bought a "piggy-back" Cyrix chip. made it a 386DX, lasted 3 months before it fried, hahahahaha.
 
That first system, as in "REAL system", was a long time after the first POS I bought, Commodore64 with cassette tape drive. I paid $400 used for that puppy, man, it sucked! :x
 
tool_462
 
Sounds like your mobo is dying, I don't think it's the PSU. Either the mosfets are crapping out, or some caps have died.
 
It's either that, or your system is overheating bigtime, which seems strange, Celery's run cool, when compared to Prescotts and the like.
 
Like jimmijo said, it could also be a RAM problem, and I agree, that is another likely culprit. If I had a buck for every RAM problem I've ever had, I'd be rich.

I've tried with my ram sticks individually and that didn't change anything, and you are right, my PC runs extremely cool. I am in my dorm room with a window open and the wind hits the back of my desk and rolls down to my pc, so right now my processor is running at 76 degrees fahrenheit. And I am led to believe that its my mobo now that i've tried two power supplies, and booted with everything unplugged except one (100% working) ram stick in there. Thanks for the responses and now it's time for me to build a new pc sad thing is, i was going to give this one to my girlfriend, her family has a Packard Bell P3 1.4ghz i think it is, with probably 128 ram tops. thanks again for all the replies!

@Relic, you should see my retro collection, not a huge one by any means but still a nice cross-section of vintage micro computing
 
@Tool, if you do find another motherboard to try out, let us know the results or if you just scrap the old one and purchase a new model, even bare bones white boxes are pretty cheap and are usually a decent configuration too.
 

Originally posted by jmmijo:

Quote:@Relic, you should see my retro collection, not a huge one by any means but still a nice cross-section of vintage micro computing  
@Tool, if you do find another motherboard to try out, let us know the results or if you just scrap the old one and purchase a new model, even bare bones white boxes are pretty cheap and are usually a decent configuration too.

 
Oh yeah, I have 2 Tualatin(unlocked) 1.26ghz, one in my wife's current system, with an Albatron ti4200, kicks butt for an old beastie. PIII 866(unlocked), Celery 1100, AMD K6 233ANR, very old Intel boards(working), and I have no clue why I keep them, heh.
 
I just sent off my ASUS FX5200 AGP to a kid in the states, upgrade for his MX4000 PCI, I wasn't using it.
 
Last year I sent off my old Voodoo 3000 AGP to a buddy in Montreal, he was putting together a system for a kid who's mom, was, well, not all that well off, worked hard, but couldn't get ahead.
 
Tomorrow I'm firing off my old Matrox Mystique PCI card to a kid in Calgary, it's gotta be better than his onboard crapola.
 
Still have an old PCI ATI Rage3D II+(something like that), I'll pass that on eventually too. I just hate to toss this stuff, someone will have a use for it.

Yeah I plan on building a pc from TigerDirect, i just want to get this PC solid for my girlfriend to use. I found a cheap mobo with an agp slot that i could toss a cheap card in to upgrade the mx4000 but it says pentium 4 socket 478, but doesnt say anything about celeron. Let me know if this would work with my Celeron 478 pin processor?
 
ECS mobo
 
I will soon be posting parts of my new pc to make sure everything is compatible, and see if anyone has any cheap recomendations.

Originally posted by tool_462:

Quote:Yeah I plan on building a pc from TigerDirect, i just want to get this PC solid for my girlfriend to use. I found a cheap mobo with an agp slot that i could toss a cheap card in to upgrade the mx4000 but it says pentium 4 socket 478, but doesnt say anything about celeron. Let me know if this would work with my Celeron 478 pin processor? 
ECS mobo
 
I will soon be posting parts of my new pc to make sure everything is compatible, and see if anyone has any cheap recomendations.
 
Yes it will
 
http://www.pcchips.com.tw/PCCWeb/Product...e=CPU%20Support

Awesome thanks Relic! I googled it but didnt have time to look through very many sites to check. Thanks again

You're welcome, happy to have helped.

You should also look into AsRock motherboards. I don't know what genius came up with that name, but the boards are solid. They are a generic white-box version of the Asus motherboard. Same high quality board, but a LOT cheaper without the ASUS brand name on it.

Yes, "AsRock", very, ummmm, interesting name brand, think maybe something got lost in the translation? Heh heh heh