Please help: System boots but no display at all. Changed LCDs, no luck.

Hello,
My dad installed the software for a new ergonomic Microsoft multimedia keyboard on his computer and since restarting after installing the drivers, the monitor never receives any signal. No signal during boot, and no signal when it reaches the windows logon screen. I don't know if the keyboard drivers installation is at all related, but just in case, I have switched back to the original keyboard until I resolve the problem.

I know that the computer has booted to the windows welcome screen because the keyboard and optical mouse lights illuminate, I can toggle between num lock and caps lock. ALSO, I am able to see that my router has assigned the computer an IP address and I am able to map a network drive and access all files on the hard drive when the display-less computer is powered on.

I have tried to remote desktop into the computer, but I don't think that option is enabled on the computer. My goal was to remote desktop into the computer and attempt to update or roll back drivers for the display adapter or perhaps perform a system restore.

Again, I am not sure if the keyboard installation has anything to do with it, but it apparently happened after he installed the software for the keyboard.

Dell Optiplex SX280
Windows XP Pro

update:
I have tried two different cables. No luck.
There is only one video port to plug into. It is a DVI port on a small form factor (sff) Dell SX280; the video card is integrated into the motherboard and not a stand-alone pci or agp card.
/update

Any help or suggestions would be greatly appreciated. Thank you.

 

At the most basic level: since you've tried 2 monitors, have you also tried different monitor cables and that the connection is sound at the PC end of the cable?

 

I saw exactly the same problem occuring recently, and it turned out that the computer's owner had simply plugged the monitor into the on-board monitor socket instead of the video card one (the vid card switched the on-board socket off, so having the monitor plugged into it showed nothing).

Check to see if it's this The monitor may simply be plugged into the wrong port.

If this isn't the case, re-seat the video card inside its mainboard slot and try booting again.

 

Hi, thanks for your replies.

I have tried two different cables. No luck.
There is only one video port to plug into. It is a DVI port on a small form factor (sff) Dell SX280; the video card is integrated into the motherboard and not a stand-alone pci or agp card.

with this updated info, any more suggestions or help would be greatly appreciated.
Thanks.