I am as of right now convinced the problem was caused by the shortcut arrow removal.
Here's how I came to that conclusion:
I formatted my hard drive and installed 8.1 clean via a USB flash drive I burned the ISO onto.
After it was installed, I installed a couple of pieces of software. Then, I removed the shortcut arrows via the registry editing technique I mentioned previously. I then rebooted.
BANG....context menu gone!
So, I reinstalled 8.1 clean a second time. This time, I installed all of my essential software, set up the desktop and Quick Launch toolbar, rebooted, and tested the context menu.
No problems.
Then, I backed up the system with Macrium Reflect. After I did that, I removed the shortcut arrows a different way. This time, I used a freeware tool I found on the web. After removing the shortcut arrows with that tool, I rebooted.
So far, so good. The context menu is working fine. So, I can't help but conclude it was the registry edit that caused the problem. The solution is to use a different method of removing the arrows.
As of right now, I consider the problem solved. If, however, it crops up again, I'll report it here. Something tells me I doubt that will happen.
Thanks to everyone who replied and tried to help me. I sincerely appreciate your patience and assistance.
Jd