Okay, tnx. 2.4 has Comodo's own installer, which they built due to problems with the previously-used 3rd-party installer. In general it does a very good job.
The issue of Windows Security Center still showing Comodo as the firewall is an issue with WSC's repository not functioning as it should - that's a common Windows issue, not a Comodo issue. It's easy to resolve. However, that would not address the other things you're seeing.
In case they're related to the firewall (and something did go wrong on the uninstall), here's my suggestion, presuming you have no other firewall installed at the moment.
If you have CFP installed currently:
Reboot into SafeMode, and uninstall by going to Start/All Programs/Comodo/Comodo Firewall/Uninstall. When it finishes, reboot into SafeMode again.
Clean the registry using an application like ccleaner or regseeker; be sure to make use of the option to back up the registry prior to deleting anything. When it finishes, reboot normally. If WSC still reports CFP, we'll address that.
If you do not have CFP (or any other FW besides Windows) installed:
Reboot into SafeMode. Reinstall CFP. Reboot normally when it finishes (so it will fully mesh with the Registry).
Then follow the steps I posted above, for uninstalling and cleaning the registry.
LM