Problems for repair & format the system.

Hello,
Dear Sir
Good Afternoon.

I would like to say that i have windows xp in my desktop system .i m facing the problems with format this system . when im trying to format or repair this operating system then i have face fatal error of windows.and its sowing some error with enti virus prob or driver prob.and im not able to access this HDD attached with another computer system.
please send me the right ans of this prob.

Thanx & regards
Brijesh Kumar