I avoid registry cleaners because some are too invasive, and if you do not totally know what you are doing you can ruin your windows installation easily, and sometimes backing up the registry will not work, I know I have been there once myself, and I am no newbie at PC security..
If you always uninstall unused programs correctly, there is very little left over in your registry to worry about, so all I run is a good free Anti Virus (MSFT Security Essentials), Windows firewall, and my routers built in firewall, along with spybot *&D and Malware Bytes.
Running just those few things have kept me problem free for years.
Nice PC guts Art, I see you have a Zalman CNPS CPU cooler, at least it looks like a Zalman, the CNPS are a great line of aftermarket coolers, I ran one for years, now I am using a Thermaltake FRIO...
2006 Pontiac Grand Prix GT with SC
1996 Buick Park Ave NA