There may be an easier way to do this than what I say, but this is how I did it.
A couple years ago, when I just started learning PHP, there was no server for me to test my code on - so, I turned my Windows XP comp into a server.
You need Windows XP Pro, however.
First, you need to install IIS -
here is a basic guide for doing that.
Then
Apache.
Then, you must install PHP - look
here.
And then
MySQL.
Hereis another basic guide to getting everything set up.
Once everything is set up, you should be able to access your server by typing in your computer's IP address into a browser. That would take you to the root directory you set up when you installed IIS - and whatever PHP scripts in there should run.
If you don't have XP pro, I don't know of any other way to tackle this problem - you might want to try a computer-support site where they have experts better able to answer your question.
Really, I think the best way would be for you to figure out how to connect that computer - PHP and MySQL run slowly just on a regular computer, and when you go to upload the site, the connecting settings would have to be changed in the PHP files. Also, some CMSs may not take very well to being set up on then transfered to two completely different environments.
Generally, working with PHP+MySQL on a Windows computer is a pain - if you can ever get it set up, it took me forever to get everything installed and configured properly. Then, every time you want to work on your code, you must make certain that both MySQL and IIS are started up.
As I said before, if there is any way you can get that computer connected, you should at least try before going this route - it will probably only lead to a lot of headache.