Networking Problem - Access to external hard drive

I have recently rebuilt my computer after a software issue - OS is Windows 7.  My PC is connected by wire to a NETGEAR DG834G v2 as is my external hard drive.  I reloaded Norton 360 V5 and was able to see and access the external drive in Windows.  However I could not see nor access the external hard drive to restore backed up files, placed there before the rebuild.  On trying to re-establish my backup plan whereby files are backed up to this external drive, I found Norton could not see the external drive.  I attempted to fix this by configuring the "My Network" tool.  This resulted in no change to the Norton Back Up situation, but did remove all access to the external drive via Windows.  I downloaded and installed Norton 360 V6 in the hope that the situation may be rectified.  It wasn't.

 

How to I regain access to my external hard drive and the critical data it contains, short of removing Norton from my PC?