Originally Posted by newparad1gm
Unfortunately, since your drives are not the same size, you cannot utilize RAID. Also, why are you looking to transfer your OS? Is the larger drive also faster? Otherwise there is no need to. You just install new programs to the larger drive from now on.
Actually, he can use RAID. It's called RAID JBOD (just a bunch of drives), as has been pointed out already. He'd have to reformat, of course, and his motherboard would have to support this config. But once complete, it would show up as one HDD, likely the C drive.