Power supply tests ok but installed nothing happens It was working ok until last nite when it shut itself off.wouldn't restart tried another power supply same result.tried an old one without the 24 volt mb connector and it powers up the machine but not mb.I tried resetting memory and cmos

See if this solution works:
http://www.fixya.com/support/r4501608-when_windows_xp_start_primary_fix

I have the very same issue.. I purchased a new power supply for $331 and after I installed it, same thing! nothing changed so it's not the power supply..

The green light means there is standby power to the motherboard.
Power button may be broken, does it 'click'?
With the case open, do any of the fans start, then stop?
If yes to the above, you may have a bad power supply. Can you borrow one to try?
Last test before it's the chip or mother board:
Remove the connectors for power from drives, video card, all but the motherboard (Do NOT disconnect small connectors on the motherboard, just POWER from the drives and video card)
Remove any expansion cards except video. Note where they go.
Try again. If it starts and fans run ok (video may not work but fans go normally.), shut it off, reconnect the video card. Try again, power off, connect or install one thing at a time until it stops running again. The last item plugged in is the culprit.
Always one item, power on, try it, then power off, try the next one.

Dear ray_dorothy,

read this article

http://www.squaretrade.com/pages/laptop-reliability-1109/


basically 1/3 of all laptops fail in the first 3 years of its life.

________________________________________________________

Issues that may cause your problem / to look for:
in no particular order.

power supply
Hard Drive
motherboard
CPU
Memory

Power supply has several voltages. Just because the 5v power is active doesn't mean all the voltages are OK. You need to have the power supply tested for 12v and 3.3v. A quick test is to unplug all the wires from the power supply. There is a single green wire on the motherboard main plug. Connect (use a bent paper clip) that green switch wire and any black wire. Plug in the power supply and it should run (fan starts)

Reinstall or update the usb devices drivers.
doesnt work? try changing power supply

I recomend that before doing anything else, unplug your TV (from power) for at least 5 minutes and then plug it back in. See if this solves the problem.

Hello,

That is a power failure, please try change the power supply..or test the voltage in the wall outlet if it rate 220 volts if not then power supply is the main causes. Sometimes the software's got conflict due to virus infections.

try to scan your computer with a potent antivirus maybe it help.

melnavz

Most commonly it is the power supply. Rarely it is the motherboard when it just stops working with no other signs. You can take a power supply from another computer and test but I bet it is definitely the power supply. You can purchase a power supply tester for around $20 or so but you can get a power supply for not much more than that and test it that way.