Recently i accidently dropped my parents processor which screwed it up and would lock up during the windows xp loading screen. So i went to Newegg.com and bought a socket 754 mobo/CPU(sempron) combo then bought some 128 DDR 333 RAM and some cheap VGA video card. Slapped em into the case and it turns on and seems like everythings up and running and working fine, but nothing comes up on the screen. Ive disconnected everything but the harddrive that has windows installed on it and the CD-Rom drive. Not sure if it could be a grounding issue with either the mobo or PSU but its really pissing me off cuz my parents are using my computer in the meantime and i want them off :P. Anyone have the same problem?

Does the hard drive have the old operating system on it? If so the computer wont boot up properly because the drivers for the old motherboard and video card are loading.

I'm not sure that's gonna make much difference because nothing loads up at all. From the time I hit the power button nothing comes up on the screen and the light on the monitor stays orange. I've switched different harddrives and still nothing. Might try putting in some other type of ram to see if thats the problem

THE HD might be burned. I recently finished troubleshooting a compuer and when i turned it on it wouldnt turn on. Initially the fans turn on for about a second but then everything shutts of. You might wanna get a new Hd , or try a different one just in case. Also make sure the mobo is connected properly to the case's switch.

I have 3 harddrives, which worked a couple weeks ago, and I've tested each one unless for some reason all 3 got destroyed spontaneously and simultaneously I really doubt it. But unlike what you said my computer stays on and keeps running until i shut it off instead of being on for a few seconds and shutting off. Only thing i can think of is either i got a bad mobo/processor, or i could've possibly received the wrong type of RAM, or might not be grounded is the only things i could think of.

In case this helps at all my parent's computer has a PCChips K8T800 Socket 754 ATX motherboard, AMD Sempron 64-bit 2800+ CPU, Kingston 128MB DDR333 RAM, SiS Xabre VGA video card, 3 harddrive and 1 CD-ROM drive.

Check for any loose connections? If the motherboard has integrated graphics, make sure the monitor cord is not connected to those instead of the video card.

Try to reconnect the power button to your mobo, maybe its not making a good contact....
Which PSU are you using ? is enough powerful?

Good job dropping thje processor, I cleaned my dads computer and took extra care even though it is a lowly emachine