Start off by downloading the HDD makers Testing Software to see if the HDD is working. If you get an error report you'll be looking at a replacement HDD but just make sure that everything is plugged in properly before performing the test.
While it is possible that the user did manage to kill the drive it is unlikely that this happened by just pushing buttons on the keyboard.
If the computer case got a heavy knock that will kill off HDD's very quickly.
It's also possible that the HDD controller on the M'Board has died so to check this out download the Ultimate Boot CD from
http://www.ultimatebootcd.com/download.html
Make the CD the first Boot device and run the Diagnostics on the M'Board CPU Ram and whatever else. If the CD will not boot and it is set correctly in BIOS then that would confirm a bad M'Board and there is very little you can do to test once you have reached that stage. But if it is the M'Board it's just possible that the DATA on the HDD has not been affected so I would try it in a different computer as a Slave and see if you can recover the data off it.
Col