pri slave

after recent xp crash.my friend installed a new xp.once every 50 times it works.but the other 49 times.it says pri slave isnt detected as well as all the rest.he has it set on auto-decet but no luck.he is not very c’puter lit so if anyone can give instrutions in plain english wud be grateful.b4 the crash his hard drive was made bigger by 64.but months b4 the crash.can someone plz tell me the proper ettings or a place where i can veiw them..thanks