Question : Problem: How do I get the USB ports to recognize a USB 350GB external hard drive?

I have a compaq presario 700.  The computer drivers are up to date however the USB ports will not recognize a WD external 350GB hard drive.  The hard drive works with other computers but not the compaq 700.  When plugged in, the external hard drive is powerd on and clicks periodically as if it isn't getting enough power, the computer does not recognize the drive that is plugged in.

Answer : Problem: How do I get the USB ports to recognize a USB 350GB external hard drive?

2.5" or 3.5" is the size of the drive. With a 3.5" drive you can expect needing an additional power cord or double USB plugs.
If the drives casing is about 12cm long -> you have a 2.5" drive. If its over 15cm, most likely its a 3.5" drive.
Pressario 700 is not a recent pc and might be unable to supply enough power trough only one USB port. (with the first external drives there was "a rule": over 80Gb => double usb connector or extra external power needed...now days pc's can deliver more power trough a single usb port)

Maybe try to look for a cable that connects this disc by using 2 usb-ports, take a look here:
http://www.cooldrives.com/usb-power-cable-mini-b.html

Good luck