heyal,
have you tried using fdisk /mbr or /status to see if it has the master boot record on the main partition? also go into cmos and manually enter the drives configs then reboot if nothing go back to cmos and select auto and make sure lba is on.
also there is a program called final data it will pull up things u didn't think existed lol its really good. just make sure installation is not on drive your recovering data from.
good luck let me know if it works.
sb