PCs won't boot? Blank screen?

[atomicstomp]

Any help would be great or just suggestions. Ok I have a room with four PCs all the same P4 1.6 Ghz / Nvida etnt 2 M64 / 128 MB / XP Pro. Three of the PCs will not boot the LEDs are on I sometimes get a beep, the fans are all running. I did swap out a video card because I thought that was the problem, but its not. The 4th pc works fine and sits on a table the three that do not work all sit on the floor. I have cleaned them all but I have a ton of mold in that room. Could I have fried MoBos due to mold?

Also, I can't turn the things off using the power button and the reset button is not working?

And the keyboard LEDs are not coming on?

[jmatt]

Black Screen on Boot

http://support.microsoft.com/?kbid=314503
http://support.microsoft.com/support.../q294/4/27.asp
http://support.microsoft.com/directo...;EN-US;q314503
http://support.microsoft.com/support.../q162/0/31.asp
http://www.kellys-korner-xp.com/xp_b.htm

[atomicstomp]

Thanks I can not get as far as the bios I get nothing. Sometimes a faint beep.