Raid problem

I have an Acer laptop running Vista Ultimate that contains 2 identical hard
drives. When the laptop was purchased, the first drive was partitioned into
C: and D:, and the second was configured as a RAID drive (Raid 0)?, so in
Windows I could 'see' C: and D: only.
My problem is that the RAID array has stopped working, and I now have 3
drives, C:, D: and E: visible when I click on Computer. If I press Ctrl-I on
startup to get into the Intel Matrix Storage Manager, I have 2 identical
drives, both Non-RAID disks. My questions are 1) Why has this happened - is
it a symptom of another problem? and 2) Can I put it back by simply
selecting option 1. Create RAID volume from the menu, or does this mean I
will lose everything on C: and D: and have to re-install?
Thanks in advance.

Andy Baker