If you do a search on the net for cmdagent.exe high cpu usage
, you will find a lot of complaints about this particular problem.
Cmdagent.exe is part of the Comodo Firewall and is known to cause high CPU usage. Sometimes a reboot is all that is needed to will resolve the problem.
Another solution is to download the latest version of Comodo Firewall, disconnect from the net, uninstall the old version, reboot and install the newest version you downloaded before reconnecting to the net.