Dear DSCowans,
It would be great if you could your complete system specs including the AV program you're using and since how long it hasn't been updated.
I'd recommend you to run 'Startup Repair' at least 3 to 4 times, just to make sure that no error have been accidentally missed by this utility. To run this utility, start tapping 'F8' just after starting your system till you see an option like 'Advanced Startup Options'. Once you click on it, 'System Recovery Options' window will open where 'Startup Repair' is listed at the top.
Let this tool scan your entire system for possible errors and apply fixes automatically. If the problem hasn't been resolved in your first attempt, follow the same meathod to re run the 'Startup Repair' program.
P.S. Starup Repair is used to fix/replace damaged system files and registries and make the system in healthy state, if anything seems nonobvious.
Hope it helps and glad to assist if you need anything else.
