Have you ever used Ubuntu and would you like to try before installing?
Since this isn't an Ubuntu forum, there may be folks over there that can help you better. But it depends on how you install Ubuntu, such as on the same drive as Windows, did you install Grub and are you seeing a boot menu?
If you like and you believe Ubuntu is installed, you might attach a copy of your BCD Store you can obtain by using the following command in an administrative command window and attach the resulting text file that should show up on your Desktop.
bcdedit /enum all > %userprofile%\Desktop\bcdlisting.txt