Anyone good with Hard Disks Drives and connecting them to computers HELP ME!

OK. My PS3 is up sh*t creek. All the data (game, music, video etc.) has gone but is still there, yet i can't see it (when i go to copy my backup saves onto it it says there's already stuff there). The guy from the Helpline said to connect the PS3 Hard Disk to my comp to search for the elusive data. How the hell do i do that?

Anyone... Please...?