To tell the truth I've never seen anyone creating websites using PowerPoint. If you don't have any background in web design I suggest you search the internet for some tips of how to start, and I'm sure you will learn with your own mistakes; I did

it's not that difficult.
There are websites where you can build a website using finished templates, and they has a user friendly UI which guides you through several steps, which is good for beginners. However you have limited things and you can't do stuff you do when you write the code yourself. (i.e.
www.freewebs.com etc...)
Personally I don't suggest those type of sites, take a look at these:
http://www.w3schools.com/ http://webdesign.about.com/
Advanced coders use only notepad to build webpages, but there are programs such as Microsoft FrontPage, Macromedia Dreamweaver etc...
What do you think?
