Sharp Mebius PC-MJ740C CD-ROM gone.

A friend of mine has this Sharp Laptop that was bought in Japan.
It's a Pentium 3.

Hard disk gave some errors after a power outtage, so we bought a new one.
Problem is, we found out cd-rom is also gone.

Now we can't find a way to install WinXP on it.

Any suggestions?
We were thinking of buying an external USB cd drive... but I guess it won't be recognized without a working operational system.
The laptop has a normal diskette drive, so it's still possible to use a disk boot, which is not that much helpful, unless winXP boot disk has drivers for external cd drive. Anyone knows if it has?

I don't even know it WinXP will run on a Pentium 3....

Real problem is that the laptop is very old, and I don't know what will and what won't work on it.
If anyone out there knows how to deal with this sort of stuff, please gimme a hand!

Tks for your attention!