Shortcut keys to shortcuts abruptly stopped working

Basic: OS = Windows 7 Pro; computer is a Toshiba Satellite L70-A
Yesterday, I had numerous working shortcuts to shortcuts (e.g. Ctrl+Alt+G to start GoogleEarth). This morning, after seeing an error message related to APO3GUI, and finding it related to DTS sound, I un-checked the DTS Studio Sound in the startup tab of System Configuration, and restarted the computer. I had not, prior to that, attempted to use any shortcut keys. However, after the restart, I found my shortcut keys had all "died." Subsequently, in my attempts to get them working again, I have done the following, in order, with restarts between each one, to no avail:

1. Re-enabled DTS Studio Sound in System Configuration.
2. Checked Windows updates and saw two Windows Security updates, KB 3212646 and KB3207752, showed as having been installed today (1/12). Uninstalled both from Windows Update.
3. Ran System File Checker -- no issues found.
4. Un-assigned and reassigned a shortcut combination.
5. Started in SAFE mode.
6. Started from "Last Known Good Configuration".
7. Did System Restore back two days.

I'm out of ideas!

P.S. -- wasn't sure which forum this would be better in, so here by default.

It can be that after a update the target program on the shortcut has been installed on another location.

Thanks for taking time to give me your thoughts! Unfortunately, a) this applies to over 20 such shortcut key setups, and b) these are not on my Desktop; rather, they're in sub-folders within my Startup folder.

Is your windows drive still as C:?

Open a CMD window and type sfc /scannow.
Reboot
Do it again and reboot.

On the recommendation of a member of the Microsoft community, I put a checkmark in the Store and display recently opened programs in the Start menu box. Lo and behold all my shortcuts worked again. Only downside is the stuff showing up in the Start menu -- I'm the kind of guy who likes bare simplicity. Like just seven desktop shortcuts. Anyway, thanks for the ideas here! I'm still suspicious of those Windows Updates -- what else would cause something which had worked fine to simply stop without me changing that setting?

Good. Please mark this treat as solved.