so the computer starts up but then locks up or bluescreens later?

that could be a heating issue.

you may have knocked your heatsink off your processor or it is loose. make sure the heatsink and the fan on top are not loose whatsoever and are making direct contact to the cpu. you can also buy something called "thermalpaste" and put it in between your cpu and heatsink if you find that was the cause of the problem. the thermal paste will help the heat flow off of the cpu and into the heatsink making your computer run more smoothly

 

still nothing

thanks for the advice, that still doesnt seem to work my pc seems to want to start and sometimes goes a little while longer but doesnt regester on my monitor. i hope this makes sense. when i used to turn on my pc it would place the win xp load screen on the monitor, now however i get nothing because the tower doesnt stay on long enough.

mat125

 

Are you certain that all your connections are tight? No expansion cards got knocked loose? Re-seat every connection and card to make certain.

Does anything rattle around, like a loose screw?

I agree w/ newb that it could be heat, but it shouldn't be shutting down so fast if it's purely a heat issue.

 

You dropped the tower?

If all the pci boards and other connections are tight and everything seems to be in place, it's possible that you have a crack in the Motherboard.