My laptop screen has gone big and blurry

right click on the desktop and click on properties then adjust the video settings to a higher resalution and 32 bit color and it will re-size it if you like that size click on the box that says accept or ok. then once it is set lock the settings in display so it does not get messed with again. If you did not do it and a kid did not do it then download the latest windows updates and scan for virus's. Some virus,s attack the video settings and can cause some problems.