Question: hi. after my cumputer was knocked off the desk by one of my cats, it would not boot up, was not a HERD fall, hit a box first then tumbled to the floor

1. it powers up - but does not boot up - the yellow light at the push button comes on, but does not go to green.

2. the small led on the mother board light up and fan on CPU runs

3. I've replaced the mother board but did not fix it,

4. fiddled around with master and slave hard drive, did not make any difference

5. tried the system resoration disk that came with the computer - no effect

6. I suspect the drop caused damage to the hard drive but this is only a guess,and short of getting a new hard drive, I cant persue this at this time, but as said I attempted the use the slave drive after making is a master by changing the junper, but no luck

7. the keyboard briefly lights up when powering up the computer but the lights do not stay on, the monitor light blinks but monitor does not go on

any suggestions thanksThe hd is susceptible to severe jarring. Were both drive internal? If so, it's not unlikely both suffered damage.Try booting from CD or USB. That might tell you what is still working on the unit.attempted with the origional OS disk, light on CD drive goes on but otherwise no change - still blank screen, no beeps, no grunting of loading OS, no lights on keyboard- tried several diffent HD but am not sure what condition they are inPut in ONLY the current boot HDD for that machine jumpered as Master...
At this point it's a proccess of elimination...
Double check all connections while hooking up the drive and remove and re-seat vid card and RAM chips with all power disconnected...Installed a new hard drive, new CPU in addition to the prior mother board replacement, and still no change - fan runs, but no screen on monitor, the indicator light on the computer, at the on switch stays rellow INSTEAD of going to green, reseated the vid card So far, it looks like the only new things you haven't put in are the power supply, CD drive, RAM, and video card. All but the CD drive can prevent a computer from booting. Generally, RAM and video will produce a beep code as well (not always though).

First, follow Patio's advice of again reseating everything and only with the one hard drive, and double check all the connections (hard drive cable and power cables).

If the computer still isn't giving you the POST, even after you've changed the motherboard, hard drive and CPU, I would suspect the power supply was possibly damaged in the fall. A damaged power supply can appear to work normally, making fans spin and such, but COULD in fact have a problem. Do you have another power supply you could put in there for testing PURPOSES?

Aside from what you've already changed, I can't think of anything else that could have been damaged in the fall. It's unlikely the RAM was damaged, as the jarring would have only knocked a chip out at most, but not likely damaged it to the point it wouldn't work.