eSATA jeopardizes RAID process

I'm running RAID 1 provided by the microprogramming of P5Q3 MB on a dual boot xp-sp3/Windows 7. RAID uses two 500GB WD green disks (I since learned these were not recommended for RAID and I am currently replacing the green by black disks). I also have an 800GB WD green disk which is non-RAID.

Everything was running fine for weeks until I connected an external disk to the eSATA plug of the MB. My Windows 7 instantly became sluggish. Rebooting did not change the situation. After a while, I couldn't even get past the ASUS splash screen on reboots.

At one point, I finally got to the Ctrl-I screen where I reset the two RAID drives to non-RAID.

I had already disconnected the eSATA drive so I couldn't tell from the data available whether the system had tried to turn it into a RAID drive. Is that what it was doing? If that's the case, how do you handle eSATA drives in this environment?