One other little glitch to note: sometimes the screen will go blank as if going to sleep, and recover in about one second. That happens only once in any boot cycle.
Back in September, Geek Squad did run its own hard drive check on this computer and found no errors. I did run Microsoft's check in September and found a few, which Windows 8.1 fixed automatically (already discussed), except for "prnprcla.inf". It's also important to note that Webroot Secure Anywhere does not find any malware.