Desktop

I assume you have reseated the video card if that is a PCI card. Have you reseated the RAM?

Does the PC not usually beep once during the power-on self test sequence?

My guess is the CPU or the motherboard.

First reseat the memory, and possibly try a different DIMM slot. When you say old, how old exactly do you mean?

Normally, if there has actually been a logical problem you will get some system beeps, telling you where a logical problem may lay. If you are getting nothing, then most likely, something has fully broken or not getting power. It is offen that a power supply problem, i suggest testing the powersupply, however, if there is a tripping fault, it may have caused damage to either GFX, SPU, RAM, or even MoBo, so I wouldn't like to test this on another valuable machine. Best idea is to use a known working PSU on the dead machine, rather than test the possibly broken PSU on a known working machine, as this could cause you two dead machines.

Also, check for any burning cornflakes smells, mainly coming from RAM, as the RAM gettings the highest baseline current from the PSU, and it is not uncommon with faulty PSUs for RAM DIMMS to actually burn, visually inspect all your contacts on your RAM, and PCI, AGP cards.

Other than that, it is a case or trying components one by one, swapping in possibly dead components into working systems.

Myself, I have made myself a really cheap working system for testing hardware, total cost was about ?180, then if when testing hardware, it damages anything, i've not blown up my Xeon or Dual Core Processors LOL.

Hope something here helps. Large local PC shops (that do repairs) may have a testing environment for PSUs, but I desperatly urge you not to test a possibly faulty PSU in a working machine.

I have unplugged and examined all PCI cards as well as RAM and processor and find no visually burnt areas and all are fully seated. I also opened up the power supply and did not find anything visually. Is it okay to use a voltmeter to test the output on the different leads coming out of the power supply?

Also, when I say older, I mean it was purchased in 1998 and I have upgraded the drives, RAM, OS, etc. All was working fine when I left Houston...but 1500 miles later...in California it has nothing.

I used to get the typical beep(s) during boot up but now nothing.

I may just end up using the salvageable parts off this machine to build another one.

Thanks for the help guys.

As you haven't answered if you are hearing any beeps there is another possibility here that the 3 V M'Board Battery has gone flat.

remove power from the machine change the Battery and power up and then go into BIOS and reset things. I think that will cure your problem as the M'Board CMOS Battery can create all sorts of funny things when they go flat.

Of course if you are hearing any beeps from the speaker in the Computer you'll need to post the model of the HP Pavilion and what beeps you are hearing. There should be a Beep code inside the Manual that came with the unit and that will tell you what has gone wrong.

Col

I have a guess that something got shaken up,but it may not be the problem,check the cmos battery or replace also it could be the temperture change of the system going from a humid area to cooler area,so humidity may be playing havoc on system.

If peripherals work on another machine then you could look at the power supply as a possible culprit also.
Hope this points you in the right direction.

Remove everything unnecessary from the Motherboard including all disk drives and cables, just leaving the video card in place, and see if it gives a post beep. If it does, and tries to boot up, replace the bits one by one until it ceases to try booting.

If it still doesn't want to boot with a bare minimum config, try a new power supply as stated above.

It is also possible that the motherboard itself has moved on its supports, and if these are metal supports, it may be shorting to earth through one or more of these. Did you transport it lying flat or standing up? If standing up, the motherboard could have suffered lateral movement due to gravity and inertial shocks.

If you can't get any life with everything disconnected, and a new power supply, and a careful re-seat of the motherboard, then change the video card. If it is an AGP card, try a PCI card. If that give no result, it is probably time for a now motherboard and processor.

And, yes, it is OK to test the voltage on the power supply output plugs to see if you are getting 12v and 5v. Another good test is to check the voltages on a power supply output plug, while the main power connector is plugged in to the board. If you get correct voltages with the main connector unplugged, but the voltages drop significantly with it connected, the problem is a short to earth somewhere.

Hope this helps.

Alan

i bet the cmos reset itself after that long time with no AC power.
tell us exactly what pavilion and what video card? also os, please?
the video problem has to be fixed first, otherwise we going blind. you have no video now on your monitor whatsoever, yes?
could you possibly both an add in video card and a integretated video card. (do you see two places to plug in a monitor and have you tried both?)
have you tried an older monitor? (in case your video card is outputting a refresh rate incompatible with your monitor)
a cheap video card might be worth a shot or maybe you can borrow one