Regarding questions about OS Compatibility for CBO v 4.26, the following is taken from Comodo's
Download page for CBO.
Windows For Workgroups 3.11 (Win32s required)
Windows 95, 95A, 95B, 95C (Winsock 2 required)
Windows 98, 98SE
Windows ME
Windows NT4 (SP2+ required)
Windows 2000
Windows Server 2003
Windows XP (any, including 64)
Windows Longhorn Server
Windows Vista (any, including 64)