netgear readynas rnd 2000 v2

The decoder ring for the LED codes is here: 

LED blink behavior for 2 disk systems is three quick blinks of all disk LEDs and the backup LED, followed by an 1s delay, followed by a number of slow blinks.  The number of slow blinks will be the error code.

Current error codes:
1  - Vendor mismatch
2  - No disks detected
3  - Bad contents on root partition of disks
4  - Flash error
5  - Unsupported RAID configuration

So in your case the NAS is detecting "no disks".  OS reinstall and factory default both require disks.

The next troubleshooting test is to check both disks in a Windows PC using vendor tools (seatools for seagate, lifeguard for western digital).  You can connect the disks with either SATA or a USB adapter/dock.  Label the disks by slot as you remove them (and power off the NAS before removal and reinsertion).  Note that if you need to offload data stored on the NAS you can use the free r-linux for windows tool (extracting data from disk 1 of the NAS).  https://www.r-studio.com/free-linux-recovery/

If you have a spare disk, you could also try doing a factory default with just that disk installed, and see if that works.

If the disks check out ok, then you either have a failed chassis or (less likely) a failed power adapter.  You can easily replace the power adapter for about $25; the chassis isn't repairable.