That depends on what you mean by "crashed".
If the drive is making horrible noises as if the heads are contacting the platters, then nothing you can do will recover your data. A "head crash" may be something that Ontrack could handle, though.
Otherwise, if your drive spins up and is detected in BIOS with its correct model number and full capacity, then your best approach would be to clone it and then work on the clone.
Some preliminary checks to determine the extent of the damage would involve examining the drive's SMART report. Look for reallocated, pending, or uncorrectable sectors.
HD Sentinel (DOS / Windows / Linux):
http://www.hdsentinel.com/
HDDScan for Windows:
http://hddscan.com/
See this article for SMART info:
http://en.wikipedia.org/wiki/S.M.A.R.T.
If the report looks good, then run CHKDSK in readonly mode. This will verify the integrity of the file system.
Alternatively, if the SMART report is full of bad sectors, then you would be best to clone your drive, sector by sector, using a utility that understands how to work around bad patches in the media. Ddrescue and dd_rescue are excellent freeware tools for this purpose.
dd_rescue: http://www.garloff.de/kurt/linux/ddrescue/
ddrescue:
http://www.gnu.org/software/ddrescue/ddrescue.html
Comparison between ddrescue and dd_rescue:
http://www.forensicswiki.org/wiki/Ddrescue
Ddrescue can perform multipass cloning. It clones the easy sectors on the first pass, and attempts the more difficult ones on subsequent passes. It can also clone your drive in reverse, thereby disabling lookahead caching. It keeps a log, allowing it to resume after an interruption.
The following thread discusses various freeware and commercial cloning tools:
http://forum.hddguru.com/the-best-disk-cloning-hardware-software-t10396.html