ICS Problems

I have a problem with Win 98’s ICS. It will install fine and work for a few days then quit. Once it quits DUN says there is no modem installed even though Device Manager show it fine with no conflicts. I then uninstall ICS…uninstall DUN and reinstall and it goes back to working…for a few days. This is driving me nuts and my customer is ready to hang me. I have also tested Sygate and it is FAR to complex for my customer to understand. Any help would be appreciated. Direct emails wouldbe appreciated.