It seems something is missing or it did not get installed for some reason.
A driver update isn't always a fix-it task, either.
The solution is simple: you need to force Windows to rebuild its icon cache!
The easiest ways of doing that is by deleting the Icon file.
When I updated the driver of my network card and restarted my computer system, I faced a strange problem.
Suddenly the "Network Connection" icon in system tray started showing a yellow triangle with exclamation mark (!