resizing problem

hello
Im having trouble resizing something because im making an enter page for my site well I started off with 400x400 so i did all my work then suddenly it was supposed to be a rectangel so when I resize something like width the height would be the same becuse its a square well I dont want a square and so it wont turn into a rectangle any help possibly?

In the resizing window unclick constrain proportions.

And in your brain click add periods and capitals so you have multiple sentences.

No offense.

tom