It's very common for firewall and antivirus software to leave behind invalid registry entries upon uninstall. By their nature, they set numerous "hooks" into the system. You may well understand that for the writers of such software (particularly if free), writing a clean tool is low priority. Norton only did so in response to numerous complaints.
I'm not aware of any registry cleaner that will really do the trick. You could manually edit the registry, but that is hazardous if you aren't sure what you're doing. It is also, IMO, unnecessary. My wife's comp has remnants of Kerio and Outpost firewalls, also Comodo antivirus (been meaning to do a clean install). They are all disabled.
Here's what you can do:
1) Go to Control Panel -> Administrative Tools -> Services. Maximize the window. Look for any entry that has "Comodo" in the title. Right click -> Properties -> Startup Type. Change to "Disabled". Close.
2) Go to Start -> Run. Type in the window "msconfig" without the quotes. Under the Startup Tab, uncheck anything that says "Comodo". Reboot.
3) Run system file checker. Start -> Run -> "sfc /scannow", without the quotes and with a space after sfc. You may be prompted to insert your install disc in the optical drive. More about system file checker here:
http://www.updatexp.com/scannow-sfc.html
The only registry cleaner I use (occasionally) Is CCleaner, free. I don't see the connection between your registry cleaner and standby problems, but perhaps someone else can advise. I'd be more likely to think some Comodo service is doing it. Disabling such services and running system file checker *MAY* (crossing fingers) fix the problem. Please post back on your success or lack thereof.
Good luck.
