How can I reload Windows XP Professional on to a Dell latitude X 300 laptop computer without a disk drive?

Windows will not start on my Dell laptop computer, it say's unmountable-boot-volume. I was told to reload windows to see if that would solve the problem. My problem is I have no idea how to reload windows, could someone please give me an idea on how I can do this? Thanks!|||the possibility is that if it doens't have a cd drive that there is a recovery pertition on the hard drive. this should be eviddent during post as it will tell you something like "to access recovery drive press alt+f11" or some such.