How to enforce the classic start menu on Windows 8 Developer Preview
I've just spent an hour looking though various W8 menu options before Googling gave me this from NeoWin: Windows 8: How to re-enable the classic start menu - Neowin.net
It's a registry entry and to quote NeoWin:
It was only posted yesterday, so good timing there!
To get back the old start menu, open regedit, goto
change value of RPEnabled from "1" to "0"
close regedit, you get your old start menu......the catch is, no more metro UI because you just disabled it. To get back the Metro UI, change the value back to "1"