I have the Asus A8n Sli Premium motherboard using the Silicon image raid controller. My OS is on a non Raid IDE drive, and I have 3 1TB drives (2 are Raid 0, one is by itself). My question is: when I upgrade to windows 7 will I lose my data on the raid drives? Thanks in advance.
Well, it's always recommended to make a backup before doing an OS upgrade. AFAIK, backups never hurt anyone.
Anyway, in your situation the RAID configuration is stored by your controller, not by OS so you should not loose any data unless you are not going to erase your RAID for a purpose.