INSTALLING RAID 0 on dual 500GB SATA

I use to be able to do a RAID 0 and everything before, but not from an existing OS.

I just installed XP PRO onto one of my WD 500GB SATA Drives. installed all my drivers and such. all the updates as need and thats it.

Now, I have read that I need to Do the RAID 0 setup up before I even install the OS.

Can I set up a RAID 0 with the OS XP PRO already isntalled on one of the HDD's, and by installing the second one (identical Drive)?

I thought I might be able to use PARTITION MAGIC. I have the newest one I got from a guy at school to borrow.

Thanks a bunch guys and gals. and is there a good software to keep this in tip top shape as well?

 

This recently came up - here was my reply:
The idea is that nVidia4 chipset motherboards do it easily; with others it's a little more complicated.