Originally Posted by nekrosoft13
well, you can do it
1) JBOD (just bunch of disk) = would have to start over again, it joints two hdd together, making it look like one device.
2) don't assign a letter to the HDD, instead assign it to a folder. so your drive C would still will be 150gb, but you would have a folder with 500gb of space.
These are the two ways I would consider doing it.