I've never used any IS, only AV software. My environment is the following: 1. I use a dial-up modem. 2. A wireless capable router is used only for printer/file sharing. 3. A Windows 2000 desktop is hardwired to the router. 4. A network printer is hardwired to the router 5. A Vista notebook connects to the router via wireless. 6. Another printer is hardwired to the Windows 2000 system and is available for printer sharing. The Windows 2000 system has KAV, not KIS. What would be the advantages of using KIS instead of KAV on the Windows 2000 desktop? The Vista notebook came with NIS 2008 pre-installed. NIS has given me nothing but grief. So, I'm thinking of dumping NIS 2008 and using KAV 7 or 8. Or, do I need KIS on the notebook?