1 you have to swap disks over. The copier buffers you disk onto the hard drive and then you swap the disk over and it then squirts it onto the blank.
If you go to any PC components shop you can pick up a second burner for peanuts and then you will be back to 2 slots.
You can use the old machine in several ways.
1. Pull the harddisk out of the old one and add it to the new one.
2. Share certain directories and attach them as extra drives on the new machine via a network.
You won't be able to directly port your programs across you will have to install them all again on the new machine