scandisk runs everytime I boot

I have a HP Pavillion running Win98SE. Everytime I boot it, it runs scandisk. I am shutting it down properly. It is impossible to install new software because when you reboot, as part of the installation process, it never completes the install. Also, it takes a full 5 minutes to boot AFTER running scandisk – pretty slow. Finally, this computer is hooked to a cable modem. I’m told it takes about 10 minutes to load the home page. I’m thinking all this is related. If I can figure out why scandisk keeps running maybe all the rest will fall into place.

BTW, the HP is 500 MHz w/64 MB RAM.

thanks,
JK