@Pastor - You are basically installing new "guts", so the motherboard doesn't recognize what is on the current hard drive. So, that needs to be re-formated, essentially wiping it clean. From the there the OS will need to be re-installed. If you do not have or know where the disks are, then I would wait before starting this operation and you will have to purchase a new OS (I would go with XP or 7, before going with
. Also, any data that you have on your current hard driver, you will want to back up to an external hard drive (i.e. personal docs, music, pics, etc...), since once you reformat the hard drive, it will be empty and everything else gone.
Taz