Recently my HD on my Gateway 700xl crashed. I bought a WD HD and installed it. when I booted the computer with the operating sys disk that came with the computer I got the black screen of death during Windows setup/ setup is starting windows. An IT friend suspected that since I had changed the video board from the original, maybe my operating sys disk didn't have the driver for my new video board. I tried a new Win XP OS disk with the same result. Any ideas?

This is not a driver issue. Maybe faulty memory, bad PS or some such.
Why did the HD crash?
Check all your connections, reseat the memory, etc.

Thank you for your help. I thought the HD crashed due to old age. It's 6 yrs old. A clicking sound came from the computer that I judged was the HD and the screen froze. I rebooted the computer and everything worked fine long enough for me to move files to an external drive but eventually the blue screen of death appeared and the computer would not reboot.
I reseated my memory and checked all of my connections. Same result.
What is PS, as in "bad ps"?
Thanks again for the help.

Power Supply.
You're probably right about the HD-clicking is a sure sign of problems.
Can you boot to the CD and remain stable?

I'm booting to the cd when the screen goes black.

There are a few threads here with "clicking" as a suspect symptom. It could also be electrical if the clicking can be heard through the speakers.

Hughv is on the right lines - note that the PSU can glitch and damage the CPU and if that's in mid disk write (even if not) that's a damaged disk. If you renew the disk and boot from the CD, then it' got to be what Hughv suggested.

6 years old? Time for a change and my money's on the mobo and prolly also the PSU.

I agree.
It's easiest to pull the PS and get it checked, or check it yourself. I've seen PS testers at Office Depot for $15.00.