Windows 98 SE shutdown hangs

Hi everyone,
I have a Windows 98 Second edition PC with Norton Antivirus Corporate edition 7.5

I intermittently am unable to shut down the PC. It hangs at Windows is shutting down. I have a server based network and have tried the following: 1.Two Microsoft W98SE shutdown patches 2.Disable NAV scanning the floppy drive on shutdown 3.Use only preferred multimedia devices(for shutdown wave at exit) 4.Set file=200 and buffers=60 in config.sys 5.Ensure fast shutdown is disabled in system configuration Does anyone have any other solutions? kind regards Marty