I am thinking about installing the public beta on Windows 7 until the Beta ends. I was planning to use Windows 7 to play some Windows game on it and deciding whether I should boot camp Windows 7 when it officially comes out. I was also wondering whether it would affect the computer. Can I install Windows 7 on my external, or do I have to install it on my internal? What happens to my external when I use Windows 7 (it's formatted for Mac)? Is it worth downloading the beta and using it? Will it affect the speed of my 2.0GHz Al MacBook? Thanks!