Windows 7 still appears as an option in grub but when i choose it, it does nothing and goes back to the grub selection screen. I have tried boot-repair but it's still the same issue. Here's the log from boot-repair : http://paste.ubuntu.com/6468928/ .
Boot
windows installation disk
then select thewindows repair
orrepair your computer
option before you go into the installation process.After selecting windows repair option,it will take you to the next screen.In that screen select the
command prompt
optionThen run the below commands,on it.
This will overwrite the grub installed in windows partition.
Atlast boot
boot-repair-disk
and click on therecommended repair
option.Now it works.