Screen is not filling my monitor size?

>-----Original Message-----
>Hi, How do I alter my screen size so that it re-fits the
>size of my monitor. I accidently and inadvertantly
>messed with the buttons on the actual monitor which
>change the size and shape of the screen and I cannot get
>it to go back by pressing them again. I just want it
>back to normal, it has been like this for about a week
>and I cannot read the things on the internet properly,
>some of them go off the page.
>
>Any help would be appreciated, if anyone knows what I am
>going on about.
>
>Thank you.
>
>Sam.
>.
>Try decreasing your screen resoluton.