Insert Windows 7 DVD in the DVD – ROM
then Keep Nexting and Repair Windows option will come then you have to click comamnd prompt when system recovery option comes then click bootrec
>bootrec /fixmbr
and enter then type >exit
then just restart the system
Boot screen will be back again 🙂
This video helped me a lot by showing how the command perform
https://www.youtube.com/watch?v=7wSL91Sude0