I have a silicon labs usb uart stick that was working just fine yesterday...now the driver isn't working and has a yellow exclamation triangle by it. What changed to make it not work, I wonder?
I had already tried all that unfortunately. It seems like windows did something with the drivers from silicon labs that they fixed in the next couple days as it works now.
For those who might have this problem with other devices though...you can simply disable the driver enforcement by pressing F8 before booting the OS.
F8 before booting will get you to a boot options menu to select Safe Mode, etc..., that does disable many drivers, but the system is pretty unusable in Safe Mode.