Yes! No Windows. Put them in the cellar. There is much less distraction if they cannot have a look outside!

• You know, little kids cannot estimate time intervalls very well. They do not know exactly if an hour or four have passed.
• I am a caring father, but there are times the kids have to play themselves, because there are things that have to be done in a family. I cannot give them 100% of my time, as much as I would love to. So you have to have some things they can do alone. Working on the computer is one such thing, but it can be a bd thing if too much time is spent just glariung into the tft -> You need to set a time limit.
• Why are you limiting other things like TV or eating chocolate ? Why should they go to bed on a given time ?