Hey everyone, I fixed my System Menu. Here is a comprehensive review of the Problem/My Solution, for anyone who uses the search function.
THE PROBLEM: Wii ( v4.1U ) Balance Board synced up with Wii Music. Go to Wii Menu and System Corrupted. Preloader still works and able to go to HBC.
TO FIX: Download System Menu v449 using NUS and Priiloader (latest version). Install with WADManager off of HBC, and it will go back to HBC when done. IMMEDIATELY install Priiloader. Turn off Wii, and test Priiloader. Run System Menu. All is working.
On an unrelated note, my Wiimotes stopped syncing. Great. I'm going through the advanced search now. I am saying this because it may be an unintended side effect.
EDIT: Just started the Wii with the Wiimote, then pressed A. It worked. Try that.