what does rescue and recover do?

[T400plus]

Ok, I ran rescue and recover...consumed 3 dvds..
If I want to chnage my Hd with a cheaper but faster and better one How can I use this DVDs?.
I know the Lenovo reserve partition may not be there but what about the rest?

T400 - 2765-T6U , 160 GB,2GB,p8400,XP(3)

[dsvochak]

Booting from the recovery dvds and running the recovery software creates an “as shipped from the factory” state on a blank (or I suppose a used) drive, which should include the restore and all other factory shipped partitions and software.