I have a laptop with Windows 98 on it. I have done extensive research into which browser is the most modern and able to be used on Windows 98. The most modern browser is SeaMonkey browser version 1.1.19 which was released in March 2010. The newest Firefox browser able to be used on Windows 98 is version 2.0.0.20 which was released in 2008. Just for comparison, Internet Explorer 6 (the last I.E. able to be used on Windows 98) was released in 2001.