I just got a used laptop (Dell Latitude 433). It's pretty old (built in 1994). Anyway, when I turn it on it says "Missing Operating System" and it won't allow me to use the dos prompt. So i put in my Windows 98 Boot disk from my main pc in order to run scandisk etc., but whenever I try to do something with the c drive it says "invalid media type reading drive C" under that it says the usual "Abort, Retry, Fail?" Do I need a new Hard drive? Also, when i tried to use an external cd-rom drive, which plugged into the parallel port, the drives provided by the boot disk would not work.