My computer (tower case w/ CPU) was dropped during transportation to a new location and hit the ground pretty hard. :-| My biggest fear was that there could be some damage to the hard drives... however, I have not tested this out, because I'm pretty sure something else broke, preventing me from starting up the computer.

When I push the power button on, I hear the computer begin to start up - the cooling fan is running, the CD-ROM drive lights register, and when I took off the case I saw a green LED lit on the motherboard, so I assume the power supply is okay. I also made sure all components were snugly back in place with all connection cables firmly connected.

However, nothing happens. The monitor screen remains black, and I'm not sure where the problem is. However, I don't believe it is a problem with the graphics card (ATI 8500DV), because I don't even hear the boot beep so it looks like it's not even getting to BIOS, let alone trying to access any hardware or OS beyond that.

What would be the most likely cause for this: Power, but no boot-up/BIOS? Could it be something that's just jarred loose? I tried to check the processor (Intel 4 1.8 or 2 ghz, I forget) but can't figure out a way to safely remove the heatsink and processor from the mobo.

I'm just trying to figure out: a) could it be just loose connectors or a broken pin somewhere; b) should I shell out the $$$ to take this to a "professional" repair place; c) or how can I find out what is broken so I can simply go buy a new mobo or processor or whatever (I just don't want to buy more than necessary to fix it)

Thanks!

Have you tried removing and reinserting the RAM, all add-on cards, etc?

A) Yes, it definitely could be that a connection got broken or bent- recheck your cables and connections again very carefully.

B) Remove any components that aren't absolutely needed for the system to boot (network card, sound card, all but one stick of RAM, etc.). If that alows the machine to boot, replace the components one at a time until you find the one that's faulty.

C) Unfortunately, the impact could have created a fracture somewhere on your mobo, and that could be hard to pinpoint. If your comfortable with the process, remove the mobo and examine both sides of it carefully with a magnifying glass.

D) Do you even hear the hard drive(s) spin up?

sounds like the processor may have been nocked out of place. Brought my computer to do a slide show once before I got a laptop and I got up there and there was no video and I couldn't figure it out. I pulled the cover off and the processor had fallen out. This was also a PII 450mhz thus the heat sink and mounting is different. But its worth a shot. Could be you broke the motherboard in transit when it fell.

Thanks all for the advice - I'm pretty good with software, but not much of a hardware person (I initially bought this as bare-bones case, board, processor and memory, added some RAM and graphics card, HD and a few extras, and that's about the extent of my PC hardware knowledge)

I just disassembled the entire thing (took a while to figure out how to dismount the CPU fan and heatsink) and cleaned the dust off of everything, checked pins and firmly reconnected all parts.

As for hard drive failure - no, I haven't ruled it out as a possibility, but it's not what is causing the current difficulty:

When I push the power switch on the case (front panel) it causes the DVD to power-up and the CPU fan comes on, so I'm assuming power supply okay (however, coudl it be that the power supply is PARTIALLY damaged but not providing sufficient power for boot?) That is all that happens. Completely blank screen, no beep, no memory scan, no diagnostics, no BIOS, no error message, nothing. It's frustrating as hell, because everything LOOKS okay and is firmly in place and properly connected. I just tried booting with the absolute minimum (disconnected DVD drive, HDs, and all expansion cards) and same result, so it's something with the power supply, processor, memory stick (is that likely?) or mobo.

Looks like I'll have to do some swapping, if I can find somebody with a P4 processor and/or P4 mobo willing to let me experiment...

I will NOT be taking it to a repair shop, seeing as they will charge $100+ and then more for marked-up parts. At the current prices, if it comes to the worst I will just replace/upgrade parts one by one (starting with my best guess, which would be the motherboard) Worst-case scenario is that I have a decent brand-new system for about the same price it would have cost me to have some repair techs just replace the motherboard. Now I'm just hoping my data isn't wiped from the HDs.

Well, since it looks like I will be repairing some parts... any recommendations on a motherboard upgrade? The computer is particularly used for multimedia work (video editing, special effects, and some 2d and 3d animation) so any cutting-edge advancements in graphics card ports or specifications would be good. I'm least concerned with processor speed or type, and much more concerned with expansions, graphics card interface, and bus speeds (FSB and high-speed RAM)

Check your processor. I just got hold of an old celeron and I put it in a machine i new worked, set the jumpers correctly, and the machine came up normally but got no video, stuck the old PII 450mhz back in and it booted right up. So my guess is your processor is either lose or broken.

I'd guess the processor as the most likely suspect as well - and the motherboard next!

If, that is, there really isn't a connector dislodged somewhere. Go back over all the connectors, taking particular care to ensure that everything is firmly inserted and that even all the wires/pins in the various plugs are firmly pressing home. sometimes you can get a plug or connector that seems to be securely fitted, but one of the wires is not firmly seated in the plug, and is failing to connect.

Strip it back to:

mobo
processor/HSF
RAM
vidcard

Everything else should be omitted until you get the system to POST with those components. Hell, even a floppy drive power plug that's been attached one pin across by mistake can stop a system from booting up!

Thanks everybody for input! I found the source of the problem! I was all set and ready to order a new motherboard (and possibly a new processor) when I realized that there is ONE main component from my other machine (a P3 microATX computer) that could possibly be swapped out for testing, and that is the PSU. Although the power supply is weaker (up to 230 max), I figured I could test the stronger one (300w) that appeared to be working on my broken PC, and plug it into my microATX P3 board to see what happened.

As it turns out, NOTHING happened. Apparently the little bugger had enough juice left in it to power the CPU fan and the DVD drive, but still must have been partially damaged and had no power for anything else. I tried the reverse (230w on my P4) and it posted and went to BIOS... so I proceeded to hook up the hard drive, and it booted to Win2k! So I'm pretty happy! I've ordered a new case and 400w ATX12v power supply, and everything should be dandy (although now I kind of have my mind set on the system I was looking to upgrade to! 2.8E P4 800 FSB w/ 1gb L2; ATI Radeon 9100 Pro mobo with ATA/133 and SATA/RAID support; 1gb PC3200/DDR400 ram; and a dual-layer 8x DVD-R, DVD+R burner... all for under $500!)