Vista hard drive write-protect error

Happens randomly. Usually when plugging in an external hard-drive from WinXP to Vista.

Solution:
> run "cmd"
> run "diskpart"
> select the drive "select volume " (list volume would list the volume numbers)
> add read-only attributes "attributes volume set readonly"
> clear read-only attributes "attributes volume clear readonly"
> go to drive Properties>Security>Owner and take ownership