1. if you got a backup of your c you don't need to download latest msdash, if you don't got a backup download ms dash and keep it ready on your pc.
2. unpack xboxhdm onto your pc .
3. put ms dash in the C folder into the xboxhdmlinux folder and overwrite the ones already there.
4. In the root of xboxhdm is a file named 'make-iso-win', run this file and wait for it to finish.
5. It will make a .iso file. (burn this file with ISORecorder or dvddecryptor), put the cd in the pc . Note: You must right click on an ISO to burn it with ISO Recorder.
6. unplug the XBOX DVDROM IDE cable, take the power cable off the dvd-rom.
7. Turn on the PC, Before the PC BIOS looks for hard drives, hit the Pause/Break key. It should pause at this time.
8. Turn on the Xbox .
9. It will boot to an error code(nr 11) regarding the dvd-rom, but the hdd will be unlocked, this way you'll get xboxhdm to access it on first attempt Now remove ide from hd and swap it to the pc
10. Hit space bar to continue booting the PC. If it takes a long time to boot (several minutes), then the HD has not been unlocked.
11. you will get a menu,now choose Option 1 (by typing "1") and press enter to boot VGA console with xbox-drive utilities (default). Type "xboxhd" when it asks you for a login. Another list of options will show up, choose option 1 again (the one that says "Build a new Xbox HD from scratch") and it will begin to format and write the partition table etc. when it asks you about C type yes and when it asks you if you would like an F select yes .
12. power down pc and xbox.
13. put the hd back in the xbox and boot.
Nice you just recovered your hard drive !!!
PS. If you get a msg about a frozen drive , just disable auto detect for the drive (xboxhdm will detect the hd even if it's disabled!)