P35-DS3R Raid - memory installation problems

Hi all, I have a GA-P35-DS3R rev 1.0 which ran a RAID1 boot array for WinXP for more than an year.
A couple of weeks ago I started noticing blue screens, driver failures, etc. Then one of the disks in the array appeared to die.
I bought 2 new disks and tried to reinstall WinXP, but I was not able to because of errors in the installation (BSODs).
Once I was able to install WinXP, but everything died when I tried to connect my USB external HD.
I tried to run a memory test (from Ubuntu install disk) and either I got errors, or I was not able to get to the memory test program at all (black screen with blinking cursor forever).
But if I disable raid, the memory test works. Apparently the memory blocks are not faulty, since I get no errors in one config and errors in the other.
Any hints of where the problem is, and what to do? Should I try to install WinXP and patch the BIOS, and then create the array?