I had installed ubuntu 12.04 on Windows 7 through wubi. However, due to some issues I decided to uninstall that. During uninstallation I messed up things badly. I first deleted the 'Ubuntu' folder in C drive. Then I did uninstall ubuntu from control panel. Something went really wrong because after that I see that the 15 GB space, which was allocated to Ubuntu, is not freed yet. If I reboot the machine and select 'Ubuntu' then it does not reboot and shows an error that 'some files are not found' (pretty obvious). I am working on windows currently, but my 15 GB memory is captured due to improper uninstallation.
I know there are some pro-users of ubuntu. If anyone of you have any idea what could be the possible solution, kindly share that. Thanks in advance.