What manufacturer? Web cam model?
Normally, all you should have to do is plug the device into your computer
and XP will recognize the device immediately (using a class driver for web
cams in the OS). Now it is possible that the software that came with the
device isn't behaving well with XP and "it" can't see the web cam. (You were
not clear in you description here.)
Check to see if the device shows up in My Computer. If it does, then you are
good to go. If it doesn't, try plugging the device into another USB/1394
port on your computer, or if you are using a USB hub, bypass it and plug
the web cam directly into your computer.
good luck!
- me
