Possible Duplicate:
How to remove the unwanted entries from the boot menu?
Use the up-arrow and down-arrow keys to select which entry is highlighted.
Press enter to boot the selected OS,
'e' to edit the commands before booting,
'a' to modify the kernel arguments before booting, or
'c' for a command-line
How to hide/delete this entry from grub2 menu in ubuntu 12.10?
