Defrag problem

[hogar13]

A month ago I tried to defrag the HD i had connected through  
USB to my laptop. Somewhere after 10 minutes my child clicked on Cancel and I'we got a coupe of messages that some files cannot be saved.
Now I can hear HD working but the computer recognizes only the USB MAss Storage box and that's all.
Can somebody please help me since I have some important data on that HD.

Thank you for any advice.

[Raptor]

Can you no longer access the contents or is it no longer assigned a drive letter?

[hogar13]

Neither. I don't see a drive letter nowhere although I have a green light on the storage box and in Safely remove hardware box I can see USB storage box connected.
Can you help Raptor please?

[merlin_2]

disconnect it and re-boot.......now power off and reconnect it.......if no improvement......go to the command prompt..C:/>      c:\windows  and type one of these commands after it

SFC - System File Checker - (SFC /Scannow)

/SCANNOW
Scans all protected system files immediately.
/SCANONCE
Scans all protected system files at the next boot.
/SCANBOOT
Scans all protected system files at every boot.
/REVERT
Windows XP: Return to default setting

[hogar13]

That didn't help.  
Anyone has any idea?
Thanks

[Raptor]

Have you tried to use the external HDD on another computer?