RAID 0 Plus Non-RAID drives

Hello,

I am new to this board but have come to this site for many years.
I have a Dell 490 workstation. The computer came set up with 2 500gb HDs in a RAID 0 configuration. I would like to reset it up this way...
HD #1 Non-RAID 500GB SATA for Win XP Pro OS and programs. #2 HD 500GB SATA 7200rpm blank drive Non-RAID for Premiere Pro scratch disk. These two are internal drives. 2 Seagate 500GB SATA drives in two external eSATA Antec cases setup as RAID 0.

This computer only supports 3 HDs internal according to the manual. The Motherboard and BIOS support up to 5 SATA drives. In this configuration the computer either locks up all the time or I get a Blue screen stating a Hardware malfunction when I try to install the Intel chipset drivers.
In the Intel RAID BIOS setup I have it setup showing the first two drives as Non-RAID members and the last two as RAID 0. Windows XP sees all 4 drives and formated each drive as NTFS. I ran the Dell 32bit diagnostics and everything checks out OK. From the HD tests to the Memory tests.
Does anyone have any thoughts. Am I setting up the RAID incorrectly?
The RAID drivers are already slipstreamed in to the reinstall CD I have from Dell. I tried slipstreaming the drivers from Dell into a Windows XP w/SP2 disk I have and I get the same problems.

Any help will be appreciated,

John