Need to make a website compatible with HTML 4.0, Netscape, Mozilla (repost from this summer)

Here is a project I posted this summer but was unable to follow up on it due to severe illness. So some of you may have seen it before, and if you previously inquired about accepting this project, please feel free to write back about it: I am the webmaster for a Christian ministry website. A programmer friend of mine did the programming on the site in ASP, but the site cannot be viewed in Netscape or Mozilla, and it is very quirky when viewed on a Mac. I'd like the site to be made compatible with these browsers. I would be very happy if this could be done without changing the programming language from ASP because of the probable expense that would be involved and the fact that my ministry is fairly low-budget. I use one master template from which I make all pages on the site, so I really only need this master template to be modified.