This is the new Metro Start Menu:
1. Open the registry editor in Windows 8.
If you don’t know how to open the registry yet, learn it here
2. Uncollapse this path HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer
3. Select the Explorer key and on the right pane you will find the registry key RPEnabled
4. Double-click on RPEnabled and change from 1 to 0
5. Either kill the explorer.exe and start it again or reboot your PC and the Windows 8 Metro Start menu will be disabled.
If you run into any problems post your errors below