My Passport has approx 300GB of data on it Plug it into any computer and after loading WD driver, it is easily recognised as a drive (allocate any letter) TODAY plugged in and it says “Unallocated” in Computer Management / Disk Management in XP Where has my 300GB of data gone??? NOW what - any i…

It sounds like something is corrupt. Try Test Disk http://www.cgsecurity.org/wiki/TestDisk Several people have had luck with it. Joe