If you are a complete novice when it comes to computers I think you are underestimating how much knowledge you need to set up a website.
Agreed that anyone can throw together some HTML to create a web page, but that is very different from designing a web site, and a badly designed site can reflect badly on your business.
If you really want to start from scratch I would start with this book. You can get it for about �10 from a decent bookshop
http://www.cookwood.com/htmlvqj/
It is a great little tutorial that assumes NO knowledge at all and starts from first principles to help you design a small web site (two pages).
After you have gone through that you will not know everything (far from it) but it is a good starting point.