Introducing Munchkin1

Hi I am from Derbyshire in the UK
I have been “volunteered” for updating a school website. I have had a little experience in that I have produces a site of my own and one for my wife’s WI. However I have still got lots to learn and hope to find some of that here.
This is not the place to ask technical questions but in essence what I m trying to do is reduce the amount of updating work I have to do by allowing the school staff (and children) to update the content themselves. I have done this for the WI. I used a server side script (php) to authenticate their username and password and allowing them update their content by typing it into a test box on a web page.
The school site is hosted on a windows server (all my experience so far has been with Linux) and my first decision is should I use php, asp or aspx ?
Lots more questions but that is the start.