i have two internal hdd's
Local disk G: is part of your second internal hard drive.
Why were you not using the second one? Why bother having it if you're not using it?
by what mechanism?
This started when you were trying to make a flash drive work, so it's hard to tell what you did exactly to create that new partition. If you would like to use the entire 931GB of that second drive instead of just the 125GB of it you have now, you can just right click it there in disk management and select extend volume. If you want to get rid of the the new 125GB drive and go back to not using the second internal hard drive, you can right click it and delete that new volume.