I used the windows installer of ubuntu 12.04 to download and install Ubuntu. I remember installing Ubuntu in different drive than that which contains Windows-7, it asked me to restart and when I did, the boot manager was missing. Can anyone understand what could have happened here? Right now, its not booting any OS.
There could be many possible reason.
To Get back windows,
Hopefully you will be able to boot windows. Now uninstall wubi and try reinstalling.
(A advice: download ISO file from the site and put wubi.exe and ISO in same directory. this will help you to avoid big downloads. Don't use alter net dvds)