Black screen

AHHHHH!

Well ive been trying to get my computer to work from about 3 weeks now but each time i solve a problem another comes up.

Everything was working and I was repacing my floppy drive in my new computer for the final steps of fixing another problem. After i did this i turn the computer on but then monitor is completly blanc. I've tried using another monitor on the same computer but the same problem. The original monitor works on my other computer, so i guess its a problem with my new computer. As far as i can tell my video card is working fine (the fan on it still works when I turn it on), ive also tried clearing CMOS(I must have done this about 100 time now).

I still have no idea what the problem is any ideas would be great.

thanks

What OS? I'm assuming windows.

Do you get anything during the boot process on the screen (computer logo, messages etc?). If so, try booting into Safe Mode and update the video driver (we had this same problem at a client site of mine and this fixed it.)

try taking out any new bits of hardware and see if it boots then