I have to wait 20 mins to play because my computer shut down.

Leaver Buster doesn't start with 20 minute queues, it starts with 5 and increases each time you leave again. If you got to 20, you seem to have a habit of leaving your games for one reason or another. Whether you could prevent it or not doesn't make it any better for your teammates.

If you are having regular computer or connection problems you need to fix them before joining a match. Having an afk teammate is one of the most infuriating things players have to deal with, and they aren't going to care why it happened if you keep doing it.

Well it's a problem on your end, so yeah.

20 minutes is not long. Deal with it.