I buy too many things?
Only buy what you really need. Open a savings account and put all your money in there and don't touch it till you get older or something comes up where you absoulty need money.
How do you help a cousin who steals things lies uses things without asking has anger fits over little things is an overall jerk and doesn't pay attention in school to break their bad habits?
If he doesn't understand that what he is doing you can't help him. Talk to him and try to make him understand but at the end of the day you can't change anyone unless they want to change.
Too many things on the TV screen?
Yes, there are too many things on screen. It's a plot to get you to buy a bigger screen (to reduce the crowded feeling) and it's very annoying.
How many things can you can do with CTRL + ALT?
CTRL + ALT + DELETE