:-\ very often after PC is booting there is no icon in the taskbar, seems conflict with the comodo firewall ??
It seems installer failed on adding some register keys. Did you approve installer accessing to register? Comodo Firewall may prompt or block the accessing.
Please try to run Comodo AntiSpam from 'Start ->All Programes-> Comodo-> AntiSpam-> AntiSpam configuration' to check if AntiSpam could be launched and works fine. If you could launch antispam, and it works fine, then you may need add antispam into 'Start -> All Programes -> Statup' folders to launch AntiSpam with Windows. However, it's a temporary method.
As I know Antispam works fine with comodo firewall, do you have other antivirus products in your system?
If not the above could be the very well known Windows XP system tray bug. To see if it is this log off (don’t shut down) then log back on again (as the same user). If the icon re-appears its likely to be the XP bug - this leaves the app running without an icon!