TOSHIBA SATELLITE L45 S7423 LAPTOP. I AM HAVING TOSHIBA SATELLITE L45 S7423 LAPTOP WITH VISTA . I

Question

I AM HAVING TOSHIBA SATELLITE L45 S7423 LAPTOP WITH VISTA . I WANT TO INSTAL XP IN IT.
I TRYED BUT I AM GETTING THE ERROR THAT IS
" SETUP DID NOT FIND ANY HDD IN THIS COMPUTER." I TRIED THIS IN OTHER WAYS ALSO THAT IS ,
1. I COULD NOT CHANGE THE RAID MODE TO IDE MODE.2. I COULD NOT CHANGE / DISABLE THA SATA DRIVER IN BIOS
AND I AM NOT HAVING ANY ADDTIONAL FLOOPY DRICVERS ALSO..PLEASE ANSWER MY PROBLEM.................. TO MY EMAIL [e-mail]