ok . if u have a lot of free space . then install , xp on another drive where there is no OS . like say D: or E: . i.e.. have 2 copies of xp itself . it works fine , no need to format.(but then again , i duuno if that'll solve ur problem coz it may not ask u for drivers again...) . if u have more space on C: ( more than 5gb free ) , use soft described here ,
http://apcmag.com/5485/dualbooting_vista_and_xp
skip it all , just read the part where u use diskpart.
BTW , why are u insisting on this , your problem is probobly solvable by other ways , try a system restore ..state ur problem and u can expect more help . plz dont be adament on this way . . .
and i dont see why my previous thread wont help ? if u can get back all ur files, wats the difference to u whether u format or not ??