Over the last 11 years I have kept up to date an Excel spreadsheet for one of my other hobbies, this started off as a single work book with 100 rows and 2 columns but over the years it has expanded to what is now 4 work books with anything up to 20000 rows and 15 columns each.

Earlier this year I started programming some software that has this and some other information / programs as a single source of information for other people, this I have put up online for anybody who wishes to use it and I have got some good feedback on it.
Over the last few months I have not done a lot of work on it but now need to update and refresh the information, add some new features to the software that I built and remove some information that is no longer needed.

At one stage I was looking at using MS Access to replace the spreadsheet but had some issues with people who have different versions of Office (2000, XP, 2003, 2007)

What I am looking for is some advice on what the best way is to do this and if anybody knows of some free software that will work without the issues of using Access.

Paul