I have another antivirus or firewall program. Can I also install Windows Live OneCare?
No. Before installing Windows Live OneCare, we highly recommend that you uninstall any other antivirus or firewall programs currently on your computer. OneCare might not run, or it might slow the performance of your computer, if you install it when other antivirus or firewall programs are also installed on your computer. During setup, OneCare checks for common antivirus and firewall programs that are known to conflict and provides means for you to uninstall them.