Firewire or USB?
You could try running Disk Utility against the drive, it may see it even if it did not mount.
A possibility is that you formatted the wrong drive when you were doing the install of Windows. Did you use Boot Camp or Parallels?
If that is the case, all your data has gone. How was the disk formatted in the first place?
FAT or FAT32 is notorious for loosing data
I have an external hard drive connected to my Macbook. while installing Win OS on Mac, the hard disk got affected.
Now I am unable to access the drive through Mac nor Win Os.
when I switch it ON, I get the following message:
"the disk inserted was not readable by this computer".
I do not want to initialise the hard disk, if i do so I will lose all my data.
Any advice would be appreciated.