My computer won't turn on anymore. I press the button and nothing happens. It doesn't make any sounds and no lights come on.

The light on the motherboard is on. I swapped my power supply unit to see if that was the problem, but worked fine on another computer.

It's a Dell Dimension 4500

Processor Intel Pentium 4 2 GHz
Installed Memory 256 MB (DDR SDRAM)
Operating System Microsoft Windows XP Home Edition


Motherboard
Bus Speed 400 MHz
Video Output Interface AGP 4x

Memory
RAM Technology DDR SDRAM
Installed RAM 512 MB
Installed Video Memory 16 MB
Installed Cache Memory 512 KB

Hard Drive
Hard Drive Capacity 80 GB
Hard Drive Interface DMA/ATA-100 (Ultra)


The power supply is 250 watts.

Anyone have any suggestions of what I could try?

Thanks for reading.

Any recent changes that you have made to the computer? It's tough to narrow down problems like this without a lot of information.

There wasn't really anything that changed before this. I hadn't installed any recent software or even moved it. It just wouldn't turn on one day. I wish I had more to go on. I was just wondering if there are any common problems that could cause this.

Thanks

if as you said, no lights was on at all, simple logic tells me there's something wrong with the power supply =P

but i'm no expert in computer

tried checking out whether there's current on the power supply ?

I had a Dell 4600 with the same symptoms, it would not power on and the green LED on the mother board was lit. It was the power supply.

The fact that the PSU worked in another PC may be because one of the voltage supplies is out of tolerance for the Dell 4500 but not enough out of tolerance to keep the other system from powering up. I suggest that you try a known good PSU in the dell 4500 and see what happens.

If the light on the motherboard is on, from previous experience my first guess would be the power supply.

Dell machines are common with Power supply problems, I once encountered the same problem too.
The fact that the Power supply may have worked in another PC may be because one of the voltage supplies is out of tolerance for the Dell 4500 but not enough tolerance to keep the other system from starting. This would be due to some components in the PSU MIGHT HAVE BLOWN ALREADY.
Maybe a capacitor or resistor.
Its best you buy a new power supply.