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!

Assuming you are running Windows, then boot into safe mode, login, reset the resolution if necessary, and then reboot. This usually works for me, though your mileage may vary... :-)

Thank you so much! I'll do it right away :)

Any luck with that? If not, then you may need to boot from the recovery partition and tell it to restore broken windows components.

Remove and re-install the graphic driver on your PC.