Trying to install Windows with no CD-ROM!

Hello, I am new to the forum, but not to computers, and I was wondering if I could get some input. I am trying to install Windows XP Home, or Pro on a Dell Latitude C400. This is the small laptop that has no CD-ROM, and it is giving me HELL to install! I have tried USB CD-ROM?s and completely forgot that it would not work. Please any suggestions would be helpful, thank you!