I have a 2TB HDD at the moment. I am planning of getting another 2tb hdd in the near future and RAID0 them. If I do this, will all my data in my first 2tb hdd be deleted?
You need to make sure that the RAID drivers are loaded at boot time before the migration. In other words, you should be able to boot from the single drive when the controller is in RAID mode. http://support.microsoft.com/kb/922976