Formatting without disk drives

[gvBlake]

I need to reformat my sister's laptop with Win Xp, but her disk drive can apparently not read CDs anymore, so there are other ways I can format it?

[Hardwareman]

If this is a fairly new computer, you can create a "boot disk" with a USB pen, but how would you get OS on it again? Ubuntu is, as I recall install from USB, in fact, not on XP also.