In order for me to run Scandisk in Windows 98 I must uncheck all the Avast items in msconfig and restart the computer, run Scandisk and Defrag, if necessary, then reverse the procedure to start Avast protection. If I don't disable Avast, Scandisk keeps starting over because it says something is writing to the disk. I tried just disabling it via clicking on the icon, but apparently that does not completely shut it down.