Hello,

I have a friends computer here, he blew the dust out of it and now it won't start up, push the power button nothing happens. There is another post on here just like this one except for I changed the PSU and still have the same problem. The LED is on, on the board, when you hit the power switch nothing happens.

Thanks

Try reseating ALL cables, RAM and cards.

Thanks, for the help but I just did that, still nothing.

Presumably the cover was taken off to blow the dust out.

Have you tried starting the pc with the cover back on?

I ask this, because some pc cases have a contact that detects that the cover is in place. This contcat is not always apparent/visible.

If this contact is * NOT * made, the PC will not start.

Good Luck - Keep us posted.

Are you sure he blew the dust out & didn't vaccuum it out?

For sure it was blown out.

Thanks

Either way, a vacuum cleaner can cause static, which can destroy PC omponents.

If you do not get the initial single POST (Power On Self Test) beep when powering on, the motherboard/CPU are not working. This can be caused by:

A defective power supply, even though you see some lights and fans working. The power supply has several voltages that it must supply. Just one of them missing can cause a problem.

A defective motherboard or CPU.

A defective device (drive, card, etc) connected to the motherboard, that is keeping the motherboard from operating properly.

If you disconnect the drives, pull cards, RAM, and video card, you should get error beeps if the motherboard is working.

Can someone tell me if there is a good schematic to check power supply voltage with a voltmeter, it is a 2X12 unit.

Thanks.

Here you go:

http://pinouts.ru/Power/atx_v2_pino...

Well, I pulled everything out of the motherboard and powered up and got no beeps. I'm trying to test the power supply now, that seems to be easier said than done. I'll report back when I'm done, I'm going to pick up another power supply anyway just in case.

Again thanks for all your help!

Update,

Tried a known working power supply and a known good working switch. Still the same problem. Should I be looking at the mainboard now?

Whatever the problem is that sure is a bummer. I feel for your friend. I would suggest sripping things down to the bare essentials. Remove the MB from the case and set on a nonconductive surface. Connect ONLY the Power connector, the square 4 wire power connector, power connector to graphics card if required and external speaker if available. No other wiring to MB . I stick of ram, graphics card with monitor, and Kboard. Momentarily move the jumper on the MBoard marked clr CMOS from the run position with power switch off on PSU, wait 15 seconds and return to the run position. To run the board, momentarily short the two pins that are for the power switch. You should hear one beep and get video. If no go, then try a known good stick of compatible RAM. Can try different RAM slots. Still no go then either MBoard or CPU is bad.
Blowing out the case MAY have moved an errant screw and shorted out something. That is the main reason to remove the MBoard at this point. If things DO work, immediately enter the BIOS screens and reset values as necessary. Look in the case at ALL standoffs to verify they are located ONLY at points where screws go thru the MBoard.

Ya im having the exact same problem as you a few posts down. Originally I believed it to be the PSU, however, after replacing that I am still having the same problem. I believe it is the Mainboard now or perhaps the CPU but I would like to do some more testing before I spend the money.