How to properly erase a DVD-RW?

I had this DVD RW and had my Windows 7 Beta ISO burnt onto it months ago. All was well. I wanted to use it for something else and used Quick-Erase in Nero 7. It finished and ejected. Then when I popped it in again, the computer hangs, nothing happens, no Task Manager, totally frozen. Nothing I can do. Also tried it in two other computers. So, I bought new DVD-RWs. I don't want the same thing to happen to them, so what is the proper procedure to write and erase? Its a 1x-2x version that I have now and its a Sony.