I'm currently having a new PC built which utilises my 2 existing 1TB drives. Windows 7 is installed n one of these.
It has been suggested that a small SSD I have is used as the OS disk and thus kept separately from all the other work, which makes sense to me. The question is: how can I remove the OS from the original HDD without compromising the rest of the data on the disk?
Eventually you'll want to delete the HD OS which is best done by deleting its partition, so you might want to move the User folders off its partition now before linking them from the new Win7, or moving it's User folders to them.
You can shrink the HD OS partition this way: Partition or Volume - Shrink if to the right, or use Partition Wizard Resize Partition Video Help to shrink to the left. Don't add another Primary partition if you reach limit of 4 Primary or 3 Primary and unlimited Logical it wants to convert to Dynamic.