Your RAID software ("FakeRAID") thinks that a drive is dead because it isn't answering. It may not be dead, but simply shut down for power saving and not telling the RAID. This is the sole remaining reason that consumer drives are cheap and enterprise drives are not.
It would help if you clicked on "manage" and posted a pic. My guess is that the first drive in your series is okay (drive 0), and that the second drive is not responding (drive 1). If this was my system, the first thing I would do is unplug the drives one at a time and plug them in somewhere else and see if it responds. Maybe an empty USB drive box? When I did this I would mark my drives.
If you keep your good drive and add a new drive, the RAID will copy your info to the new drive, probably asking you first. Before you do this you must make sure that you know which drive is which, and physically mark them. Once you okay the copy, if you have the drives mixed up it will copy the blank data onto your good drive.
Regarding the bad drive, maybe it really is dead, or maybe it's just underperforming in the RAID. So I would not throw it out without trying it in a variety of hookups.
When I used a 2-drive RAID 1 for backup in workstations, my minimum setup was 3 drives: 2 online in the RAID and 1 offline as backup. That way I had protection from accidental overwriting, for example if I restored a RAID from a blank drive (did that).
