This may be a dumb question, but by the way you phrased your question, it may be valid.
Do you have WIN95 running right now or some OS? Or do you only have the 98 Upgrade and are trying to install an "upgrade"? You must have an OS, WIN95, in order to use the 98 upgrade software.
And YES, UNIX ( ie Mandrake, BSD, Redhat, etc...) are fairly easy to install. As to whether they will work with your hardware you will have to find out by installing.
They are fairly compatible; I have only seen problems with video cards running the Xwindows functionality.