Re: PLEASE HELP! Rectangular blue and yellow bars appear randomly on my monitor, especially when playing video!
Video cards can overheat if they are covered with dust. The video card doesn't have to do much just web surfing, but at other times when needed it will heat up and if it cannot keep cool due to dust, it could cause the problems described so it's worth the effort to clean it to see if it helps.
Not installing Microsoft security updates would be a mistake in my opinion.