Hi
Is that all one partition c: or a c: & d:
You need to boot up from a windows DVD
Take advanced options and format the partitions
To erase all data untick quick format
Alternative boot from a live Linux cd or Hirens cd and format c: (& optionally d
Alternatively remove disk and put into another PC, and format
There is no uninstall Windows program unless you upgraded from an older version of windows and c:/windows.old still exists and you want to go back to the older version
Regards
Mike Barnes