Cannot access NAS unless I keep changing NAS Host name

what happens if you enter \\10.0.0.2\backup in Windows Explorer on one of the Win7 machines?

When I type \\10.0.0.2\backup in Windows Explorer I get "windows cannot find '\\10.0.0.2\backup'. Check the spelling and try again"
If I then go and change the NAS network name in Dashboard and try again it opens the folder name backup.
What do you want me to try next?

Ok. So since the problem also happens when you use the IP address, it is not directly related to the host name itself.

Just to recap (let me know if I am getting something wrong!)-
1) this happens only after you reboot the NAS. Once a connection is successful, it is ok until the NAS is restarted again
2) the connection fails even when you don't use the host name
3) Rebooting the PC does not help
4) waiting and trying again later does not help
5) The NAS responds to ping, and http reaches it.

What happens if you change a different setting (not the host name)? For instance, disabling SMB and then re-enabling it?

yes that makes sense.

1) correct.....every time I reboot the NAS the same problem occurs
2) correct...the same happens when using the ipaddress
3) correct
4) depends how long your talking about...I've left it more than an hour and the problem doesn't go away
5) correct...I can ping 10.0.0.2 and also load up the dashboard

When I disable SMB and then re-enable it works!! I can browse the NAS....BUT it was like I explained above...I only see media and backup....my volumes don't show up until I try to enter media and get the password prompt from Windows..then I can go back and the volumes appear. I think this is a separate issue (or maybe my lack of understanding) but we have established that turning SMB on and off does the same thing as changing the NAS network name
Are we getting closer to working out what it is and why no one else is seeming to have the same problem as evident in lack of threads like mine?

It sounds to me like the NAS is not properly starting up the SMB/SAMBA service when you power it on. Changing a network related setting forces the service to be re-started, which is why it "fixes" it. I don't know how the NAS got into that state, and of course this is just a guess.

You might try doing an OS reinstall from the NV+ boot menu (being careful not to do a factory reset!). That won't wipe your data or settings, but it will reset your admin password back to "password", so you will need to change it back. There are no guarantees here, but it is possible that it will clear up whatever is causing this, and it is easy/safe to do.

If that fails, then I see two other options:

a) create a support request (support.netgear.com), and request level 3 support. Maybe one of the Netgear support folks who monitor the forum can help expedite it. When you do get a support case, edit your first post on the thread and add it to the end of the subject. That allows Netgear to connect the dots between the posts and their support database.

b) backup the NAS data, do a full factory reset, and then rebuild everything from scratch (and see if the problem goes away).

I think your volumes not showing up is a different issue. They require NAS admin credentials to see them, media and backup don't. If you are using admin as your windows log on, you may have to live with entering the password every time you boot up the PC. I have to do that on one of my vista systems. If you aren't using admin as the windows log on, then you should be able to fix that with the credentials manager. Wait until the first issue is resolved, then take a look at this one.