unable to format partition:disk may be damaged.

I have a dell inspirion netbook mini. I am using windows xp and have had to re-instal, but get this message... how do I fix it so that I can install windows? I called Dell but they were no help because i had not purchased the "software"warranty only the "hardware"warranty. I need to fix the problem asap so my daughter can get the netbook back to school work.