OK, you say the OS drive is toast. That makes sense, but booting to an old OS drive and still getting red is concerning.
We need to figure out if it is a drive problem or a hardware problem.

The best way to do that That I can think of is to pull all the drives (since you know the OS drive were good).
Then get one known good blank drive at least 500Gig to 2tb and place it in the lower bottom bay.

Then power up the server and waiting with a paper clip watch the lights and you should see the red/blue/red/blue/red/blue 3 times, then press and release the tiny button in that tiny hole front lower middle and the light should go to an aqua/purple color.
If it does, then that means it went into recovery mode and it is most likely a drive problem.
If you start getting red lights again, it could be a hardware problem.

Let us know if it will go into recovery mode on a blank drive and then we can go from there.
Good Luck

_________________
[X510 CPU/RAM/All 2 TB Red's] [X510 CPU/Sync'ed Backup/All 2 TB Hitachi's]
[X510 /2 in box]
[X710 LIAN LI DIY W2016E] Stablebit Drivepool [EX-503 LIAN LI 5-bay USB3 External]
Fear the Cloud