my pc freezes

When I switch on my pc (xp pro sp2) and windows starts, sometimes (30% of the times) it stops. It displays the little clock in the icon bar (down in the right on the screen) ant it stops charging the other programs (in the same bar). Then the the clock stops (showing the same time) and the pc freezes (mouse blocked, etc.).
Then I have to stop manually my pc and switch on again hoping that it will success.
I looked in the log files of the system, but no error occurs.
But I noticed that this never happens if I turn off Comodo firewall ( before logging off from windows (in order that next time I log in the firewall is disabled).
I don’t know if it depends in Comodo or not, but if someone experienced something similar and he succeeded to risolve the problem, I would like to hear from him his suggestions.
Thanks in advance

Could it be possible that your previous installation of ZA was not completely uninstalled and some remnant is causing a problem with the CFP installation?

There have been many users whom have had problems due to incomplete uninstall of ZA.