Recover files from my excternal hard disk

Hi all,

I am in need of some desperate help,last week my hard drive became unacsesible and was adviced by apple store to use a program like disk warrior.

A friend of mine said he could do me a copy of DW4.4(which i believe he down loaded. I have followed all the instruction but am unable to boot from the disk and when i run program from applications it says that the disk is in use and to either quit aplications or hold c while restarting.

Has any one else had this problem? or do you think its because its not a product registered to me.

If all else fails can any one recomend a repair service in north london.

Many thanks in advance.