How do I set my 2 hd to work as a Raid Array

Hello,

I have Windows 7 64 bit. Originally my PC had 2 smaller drives working as a striped array. I removed the 2 drives and replaced with 1 2tb sata drive. 2 weeks later I bought an identical 2tb drive. I installed the 2nd drive, activated it in the bios. The bios setting is "Raid On". The 2nd drive is partitioned with 1 partition.

When I boot, the 2 drives show as "Non-Raid" drives.

How do I get my 2 drives to work as a striped array?

Thank you.