Dude....the problem is that you have 2 hard drives with the same exact drive letters and the same exact OS on them. In bootup, your machine is going to look at the system partition for the boot files. When there are 2 c drives, or what have you, with the same information for boot parameters it defaults to the master then doesn't know how to read the slave. Take the 4 g drive out. Run the 6 g by itself and fdisk it. Then, bring the 4g back in the pic as master, and the 6 back as slave. Make sure your jumper settings are correct. Boot up with your 4 g OS and format the 6 g drive from there. It should work. I had the same problem when I did the same thing about a month ago.