why does my website's look change if i turn on xammp on locahhost?

If you turn it off how are you able to view your site locally?

Right, but I didn’t know that until you just told me.

The reason is that all the links, images, css etc are linking to localhost. Have a look at the source on the page. The page looks fine when you have xammp on because it can access those resources. However the rest of the world sees what you see with xammp off.

You should do a search and replace on you database to replace localhost with the site address.

See: http://codex.wordpress.org/Moving_WordPress

http://wordpress.org/plugins/search-and-replace/