Paterbrat,
Without any info what so ever about your comp, I am going to take a stab in the dark. (I might have better luck tossing darts at a dartboard while blindfolded though.)
You should be able to open the Drive Bay if it is a Notebook Computer and remove the Hard Drive, you could try reconnecting it to see if it will work or not. (There are also adapters that will let you use a Notebook Hard Drive on a Desktop Computer so you can hopefully get the Data off of it.)
You should be able to remove the case, if it is a Desktop Computer, and check the cables to see if the Hard Drive is still connected. Also with a Desktop, you can remove the Drive and connect it to another comp in order to remove the Data.
Take Care,
Richard