Need help with RAID 0 set up

Unfortunatly not Duh, I answer your question in the next paragraph. Also: It is redundant to have 2 different sized drives in RAID 0, because you will only see maybe 2.1TB if you're lucky, maybe more.

But back to the original question... I would take at least 1 of those 200GB drives, and do a FULL BACKUP through inside Windows onto that drive. Once it is done, setup your RAID array, then boot from the Windows Install DVD. With the 200GB drive in, select "Repair your computer" from the menu that says "Install" and select then when prompted, select "Restore from backup" then point at the backup on the 200GB drive. You should be able to have everything exactly how it was. You will, however, have to go into the Disk Manager, and extend the partition (because the original version of Windows only knew there was 2TB, so it doesn't know what to do with the rest)

TL;DR: Backup onto 200GB drive, setup array, restore backup

Cheers!

Simple answer NO.

you cannot create a RAID 0 array without distroying all the information on EVERY disk in the array.

btw.

I would NOT reccomend putting the 2 mentioned HDD's in RAID 0.

2 Problems

1. there is a BIG difference in speed between the drives and the 7200 drive will have to slow down in order not to corrupt data.

2. In a raid 0 array you will loose 1tb of space from the larger drive. so infact you will have only around 2tb (TOTAL) storage at the speed of the 5400rpm drive.
instead of 3tb of storage and 1 fast OS drive and a slower data drive.

if you want to do RAID 0, get another 1tb 7200 WD drive. and raid those 2 together.