hi mehdi,
i see quite a few posts from you regarding Simatic S7 and MPI... i'll try and share what i know.
Simatic manager works fine on WinXP home without any issues. I use XP home on my laptop.
Connecting to CPU 312 requires MPI converter from siemens. DO you have the part? Incase you have the serial cable and dont have a serial port on your laptop then you need a serial to usb converter. Buy the usb to rs232 converter from prolific / belking... they both work fine.
Opc Server and PLC sim... I dont think thats possible. I use matrikon OPC simulator while developing test applications. Lemme know if u want more info about it...