There was a problem in my Windows 7 desktop a while ago. Supposed to be, there were two Gadgets in there, and I noticed the other is missing. I thought maybe I just accidentally removed it, so I decided to open the Gadgets menu to place it on my Windows 7 desktop again. BUT when I right click and select Gadgets, nothing happens. I tried choosing Gadgets again a few more times, but the Gadgets menu really would not show. I even tried going to Control Panel -> Appearance and Personalization -> Desktop Gadgets, but still, nothing happened.
I searched Google and found a forum with the solution. It was very simple, actually.
Solution to missing Desktop Gadgets or cannot open Gadgets menu in Windows 7
A possible solution for your problem is the one that worked for me, which is simple:
Right click on your Windows 7 desktop, choose View, and uncheck Show Gadgets. Then, right click again, choose View, and check Show Gadgets.
This restored my missing gadget AND allowed me to open my Gadgets menu again (yay). This solved my problem without computer reboot.
If all your Desktop Gadgets are missing, it’s possibly caused by having “Show Gadgets” unchecked.