In the 2 clips you posted in

In the 2 clips you posted in your first post the exposure of the original footage looks fine so check that your computer monitor is set up to display a good image. Yes, software like Movie Maker can be very limited in what they can do. Fine control of exposure and colour balance, etc, is what you find in professional editing software. There are quite a few consumer video editors available, both paid for and free, so it may be worth your while checking out some of the others.