I recently came across a site called Wufoo
(how web 2.0). It allows you to create forms with fields, pull downs, check boxes, etc. without having any coding experience. It`s a drag-n-drop interface that gives you the code when you`re finished. It`s pretty customizable. The cost works on a subscription basis but in my opinion, the fees are nominal if you`re getting business.
I recently used it to create a form on the "inquire" page
of my new site. I figure if business picks up enough and income is good, I`ll pay a web developer to do redo the form so I`m not paying a monthly fee. But for now, it`s cheap enough to get me started.
I don`t know if it would work for your purposes or not but I thought I`d suggest it. You could create a series of pull-down menus for people to choose the options of a custom computer build.