Ok....
Are you trying to buy a computer off of someone here? If so, you are going to have to get some more posts to participate in the Buy/Sell/Trade forum, which is where trading takes place.
Or, if you are going to build it yourself and just need a list of parts, then you are going to have to tell us a bit more info. We need to know:
-What your budget is.
-What you use your computer for.
-What, if any, parts do you currently have/need.