The GUI reports “COMODO Application Agent is not running” in the status bar, with a big red X. But the Agent IS running, I can see that in both Task Manager and Services. Diagnostics found nothing. Looks like the GUI cannot manage in talking with the Agent. I’m running Windows XP x64, I have no other security software installed, the Windows Firewall service is disabled. I can provide any other details upon request.
Thanx.
Hi Katy,
Can you please go to http://support.comodo.com (the official support centre), register and lodge a support ticket on this.
If possible, please include all relevant O/S and environment info, and screenshot, if you think they will help.
You will need to register again, as your forum credentials do not flow through to teh support centre.
Cheers,
Ewen 
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Same problem…
I’ve got Comodo 3.0.18.309 in my laptop without any problem (Vista, nod32, spybot).
I’m using exactly the same configuration but with winXP SP2 in my desktop pc and I have this message too: “Application agent is not running”.
Reinstallation doesn’t fix the problem.
Any suggestion?
Thanks
Try uninstalling, booting, then going to ms configuration and disabling all the unnecessary startup stuff. Then install cfp3, boot again, reenable the msconfig stuff, boot again. There have been a number of reports on loader problems that this has fixed, and once it is fixed it seems to stay fixed. Unless you do another clean install. 
Problem appears related to Vista elimination of the use of the boot.ini text file and going to an algorithmic approach for handling the boot sequence that seems to cause problems with CFP3.