Wd passport essential is not starting

WHEN I CONNECT IT TO MY PC, THE PC ASSIGNS A DRIVE, BUT NO LONGER STARTS UP, IT SAYS THAT THE DRIVE NEEDS TO BE REFORMATTED AND I HAVE LOTS OF DATA IN IT, IS IT POSSIBLE TO DOWNLOAD A DRIVER UPDATE TO FIX THIS PROBLEM?

Sound like a data corruption problem, try using a data recovery program, check the link below for some examples.

http://www.cgsecurity.org/wiki/TestDisk

http://www.piriform.com/recuva