This question already has an answer here:
My setup is GnomeShell Remix 12.04 and Windows 7 dual boot. Now everything works fine, however, I rarely ever boot Windows and I would like to remove the Windows entry from my Grub menu completely and remove the recovery and memtest as well. That way, I hit power, wait a few seconds and I have my login screen, but if I ever get the urge to play simcity, or WOW, or anything else that runs better in Windows 7, then I insert USB, reboot, select Windows 7 and away I go.
Is this at all possible; I'm sure it must be, but I'm just not sure how to go about it. I'm ok with terminal, so I'm not scared to have a go, so any help/advice would be appreciated.