The problem is that not all software designed to run under Windows 95 or even 98 will run natively under XP. The software with the biggest problem is that which was designed to run on DOS - As DOS-based applications are now all but unheard of, there isn't really support in XP and as such, most applications won't work without a fight if at all.

Your best bet would be to right click on the executable of your software, select Properties and then head to the Compatibility Tab. From here, you can enable compatibility mode which will attempt to run your software under a psuedo Windows 95/98 environment which may allow you to use it. It's not guaranteed nor is it perfect, but I've got old applications and games running with it before and it really is your best and one of your only options short of installing an earlier version of Windows on a separate partition.