The big question is: What do you mean by 'crashed'?

Obviously check that the problem isn't in your power source or the adaptor cord connecting the disk to the 'puter. You do this by switching round connections to lines you know are good.

If the disk does not spin - big problem.
If the disk spins but sounds funny (one of the common sounds is a repetitive tapping called 'the cllick of death') probably a big problem.
There are recovery services out there that can get your data back at a cost of from 5x to 10x what your hard drive replacement cost is. Do not assume that your data will come back the way you remember it, i.e. you may well have lost the hierarchical data structures, so the organization of files may be flummoxed.

If it is a matter of the disk spins and sounds fine but the computer doesn't recognize it (it won't mount), try mounting the drive on a different computer and see if it the drive is recognized. (If it is, GET THE DATA OFF ASAP, don't assume the problem has gone away, it probably hasn't).