pilotbrian0 thank you very much for the reply !

MY manager is jumping when i told her i might need to purchase two HD! Actually the station involve is a production PC( they will need to shut down the production line inorder for me to do that!) Therefore my repair must be short .. the station is old and dont think it comes with the original windows 2000 CD.
So i bet my best try is
1) to go ahead to rebuild using the mismatch option
2) Use the reinstall option, BTW how to back up with a ASR option?