I guess the first thing you should do is to slip one of the sides off and take a look!
Write down anything that looks like a Motherboard Type number, then tap it into google putting motherboard after the numbers and letters.
You be surprised how effective this is bringing up articles and often telling you the make, once you have this, visit the manufactures website and download what you need.
You will find that most of what the board needs will be loaded out of the generic files in windows 98, it will be things like onboard sound, lan, or graphics that will need downloading from the makers website. Martin Vote if you found this post helpful please!!