Unable to discover MBLD in Windows 7

I have installed a 4TB MBLD on my router and am unable to discover it in one of my Windows 7 Pro PCs. I can discover and do backups on a separate Windows 7 Pro desktop and Windows XP laptop.  I have the latest firmware update, the MBLD has a static IP, I have verified UPnP enabled on the router, all computers are in the same Workgroup,  I have turned off all virus software, I have tried using the WD Link software, I can find the MBLD in my network and map the drive and access the shares that way but neither the Smartware nor Windows backup can discover the drive.

I have contacted WD customer support 3 times and even gave their level 2 support tech access to my computer and he just gave up and said it was a network problem. I hardly think so since the two Windows 7 computers are running the same virus software and all the computers go through the same router.

Anybody have any ideas?

Did you have any firewalls enabled?