Power shut down and now computer is not normal

The baby pulled out the power plug when I was working on the internet (Chrome) and when I turned the computer back on again several hours later the screen resolution was massive (but I've changed the screen resolution so that's fine) and when I scroll down it does this: a line goes down the screen sort of updating it to what was lower and if I use the scroll bar on the side it is literally stuck until the whole screen is updated. The lagging and updating thingy also happens when I move a small box, ex. a word document that is restored down. A line bringing up the update must finish before the box moves. It really is annoying, and please help someone!