Netgear NAS - no internet connection

Chances are you assigned the NAS a static IP address that is now outside the range of your current router's sub-net.  You should be able to confirm that with RAIDar.  The fastest way to fix that is an OS re-install from the boot menu, which will reset to DHCP and also reset the admin password to password.  Just take care not to do a Factory Default, which wipes your data (unless the data is so old you don't care, in which case it might actually be a good idea).

The other way would be to set your computer IP address to a fixed value in the same subnet as the NAS, connect the PC and NAS together, then go in and change things.

Once you get access, you should update the firmware.  For the ARM series', there is a special order for update, so do read the instructions in the release notes :ReadyNAS-OS-6-Software-Version-6-10-2 .

I purchased a 102 with really old firmware and the online update process properly followed the steps, but I still recommend you look carefully at what it's offering to update to before you say "go".

To avoid this issue in the future, it is best to reserve an IP address in the router instead of assigning a static address in the NAS, if your IP gives you that access in their router.