i have installed Ubuntu OS as "install inside windows".when i've been running Windows unfortunately i deleted the Ubuntu files.i couldn't recover them.now the problem is, the shortcut to choose Ubuntu OS at boot time can't be remove.
plz tell me how to remove it.

Under Windows, right click on My Computer and click Properties. On Windows Vista/7/8, click on Advanced System Settings from the left pane. Click the 3rd Settings button (under Startup and Recovery) and choose your operating system from there and uncheck the wait time checkbox.

If it's a broken shortcut in W7 loader that you wish to remove, then use BCDEdit via the cmd console. It's a pest to use, because you need it so rarely, and the command structure is obtuse, hence I find I must look up the guide every time. But there are guides on the web, and it would be best for you to find an example that suits and follow that. If you manage to break the loader, the W7 disk can repair it.