Can't get popup form to go away on windows 98 startup.

Most puzzling problem. Every time I boot up my computer (using Windows 98),
a popup screen comes up  entitled - Install CompuServe 4.0 self extracting -
do you want to install CompuServe 4.0.? Then it gives a yes or not option.

CompuServe is not on this computer. I chose no and everything works ok. It's
just a very annoying thing that might have bad effects down the road.

How do I make this go away?

Any assistance is greatly appreciated.