Dell 4400 Main power in house went off while using my computer and then went back on about an hour later. Now when I try and restart the PC, the power button light turns yellow like it is in sleep mode but I cannot restart the machine. Just a slight hum fro the fan. Has the power supply fried or is there a jumper inside that I can flip to get it to start up ? Any ideas ?

Hello here is the homepage:

http://www.dell.com/support/drivers/us/en/04/Product/dimension-4400

To clear the CMOS values
1.Turn OFF the computer and unplug the Power cord.
2. If your motherboard uses jumpers move the jumper from pins 1-2(default) to pins 2-3. Keep the cap in this position for about 10-15 seconds, then move the cap back to its original position.
If you motherboard has only two pins for CMOS reset , then you may use use a metallic object like a wire to create a contact between the two pins for 10-15 seconds.
3.Plug the power cord and turn ON the computer .

The bios can also be set to reset, by removing the cmos battery.

Hope this will help you.

It seems like it that you have a faulty power supply. Also the motherboard may be damged aswell, But most probably you can fix your PC by changing the power supply.

try removing the battery . wait 30 minutes. plug the battery back in and try again.

you in the correct area you first delete all containers then re do the scsci drives follow the menu space to selct the drives then you inisalize not format if you format each drive you will be workng for hours on format make the containers then let the contoler check consistancy you will be finished in 5 hours

check power supply in back to see if you have on and off switch but you would'nt be the first with this problem from dell about the power supply going out meaning:

if you don't have nothing happening when your trying to boot the computer then it's the power supply, plug in computer power up and feel in back to see if the fan is blowing if nothing power supply is gone call dell.

Try unplugging the computer from the power supply,,and remove the battery,,,then replace battery and plug into power supply again,,,and try to restart.

Try removing the battery from the motherboard if its not soldered and leave it for an hour then out it back in, that might reset you bios and fix your problem.

inside the pc there should be a green light. called flea light. if its not on.. then id say motherboard or power supply are bad.
take power cord off. and hold power button down for 10 ecs. then reconnect and retry. i think its abad psu.

These are signs of either a faulty video card, memory issues or a defective power supply. Im probably goona lead towards a bad power supply then I would try the rest. Any questions just email me again.

Good luck.

Sure hate saying this but your dell 4400 board is the trouble.
Just finished reading a bunch of post. Double check Dell's web site too. No lights lit on the back of the PC means no power & the green led you see on the board is telling you that the board has power.
Seems your not the only person with the same problem as with other 4400 owners.
One user called dell & stated the problem he had, (just like your problem), to the letter. Dell admitted there is a problem with the 4400's. mainboard. Dell does not go out & replace every board. They, like every company wait till someone has this type of problem & contacts the Mfg. Your 4400 was made back in what 2003 - 2004. If Dell still supplies your board the best they'll do is sell you a refurbished board.
I think your better off buying a new board & fitting into your Dell case. You can try to find a board that will run your current componets.
This is dell's web site link for the dell 4400.

Good luck & thanks for coming to FixYa.