I have no idea what could possibly be causing this, but for some reason the arrow overlays for the shortcuts on my desktop literally keep changing every few seconds on their own. As I sit here and type this, I'm watching them all change between the arrow, a padlock, the rotating "synchronizing" and "complete" check icons for the Dropbox tray icon, no icon overlay whatsoever, some other arrows, and others. How do I make them stop????

I suggest you fully scan your computer, you can use Microsoft Security Essentials. Do you have a backup? If the issue persists, a system restore could help you. Regards, Miya Miya Yao TechNet Community Support

Try Clean Boot the computer and see if the issue is persists. Regards, MiyaMiya Yao TechNet Community Support

I suppose if I need to, I must restore. A scan came up clean. I am noticing a trend, however. This only seems to occur when the processor is under continuous high load.

Try Clean Boot the computer and see if the issue is persists. Regards, MiyaMiya Yao TechNet Community Support