I don't see that theme in the marketplace, so it's hard to say exactly what you'll need to do.

More than likely, you'll need to edit the CSS of the theme. If you have a URL that you can post, so I can see the theme in use, I may be able to tell you what you'd need to change.

Another thing to keep in mind: site widths are relative. There is no "normal." What is too wide for you may be perfectly fine on someone else's monitor with a larger resolution.

this the link to my homepage with the theme in usehttp://www.etrendview.com/c5 and i don't even know how to edit the css.thanks for your concern.

The theme you are using has a set width of 1128px. Changing this theme over to a liquid layout (one that expands and contracts to fit your monitor width) would take some CSS work. Probably anywhere from 1-4 hours for someone who knows CSS. There are a ton of people out there that could do this for you (myself included).

If you do not want to pay someone to do this for you, I would recommend you look for another theme. Make sure it has a liquid layout.

Also, for your reference, I've enclosed a screen capture of what your site looks on one of my machines. As you can see, it fits well within my monitor resolution.