Cannot login to admin page or get RAIDar working please help

First off, if you have an RND2120, it most likely is not a V2.  AFAIK, Netgear didn't sell the V2 with drives, and the "120" part of the model number means it shipped with one 2GB drive.

I don't doubt you believe you bought a V2, as Netgear made a huge blunder in naming it and many used ones are sold misidentified.  Netgear had already used v2 and v3 (note the small v) to designate a small, inconsequential hardware change to the original Duo (which is now referred to as a V1) and put that on the thin sticker on the bottom of the NAS.  They later completely redesigned it, including an OS incompatible with the V1, and called it a V2.  The "real" V2 says so right on the front,  A V2 also has a centered rear fan the entire width of the NAS, where the one on a V1 is offset and smaller, and a recess for the power supply connection.

This is important because your issue is that that ancient NAS does not support TLS above V1 and TLS V1 has been depreciated in all modern browsers.  But how you can resolve that depends on which you actually have.  There is a patch available for a "real" V2, but the only ways around it for a V1 are to use an older browser or make a change such that it uses HTTP instead of HTTPS.

This subject is covered by dozens of posts already on the forum, and you can search for them (but use Google, not the built-in search, which is abysmal).  Or, if you confirm which version you really have, maybe somebody will post that information for you yet again.