Let’s say you are like me, you are able to change a wireless card in your desktop but are no computer expert AND are running Windows 8 or 10:
Before doing anything else boot the computer and hit RESTART. Not SHUT DOWN but RESTART. For Windows 8 and 10 this not at all the same thing – here ‘shut-down’ is more like what ‘hibernate’ used to be for W 7.
The point being that if the computer has some updates pending (which would have been installed the next time you would have wakened it up) and you change something in it (a wireless card, for instance, 😉 ) it will have some trouble sorting things out. It will succeed, eventually. but it will take some time and it will get you worrying.
So hit RESTART first and open its belly afterwards.
Don’t be sad when it ‘freaks’ out, for any reasons. Just take it as an opportunity to reinstall the OS. It will feel like a new computer. If you played safe and had everything backed up, of course.