Grandmas Computer Cant Find Internet, PLEASE HELP!

Hello!
Im currently sitting here with my very upset grandma, because her computer cant connect to her internet.

The computer says its connected, but that there is no internet access. Every other device in the house can connect, but not her computer.

I've already tried searching and following some of the other suggestions in here, but almost all of them tells us to download something, which is pretty impossible when theres no internet access.

I cant figure out what she did, but she says that her "Avast" (she has it because she doesnt want her identity stolen.. Im serious.) anti virus program told her, that a firewall was not turned on, and asked her to turn it on, but it would'nt allow her to do it.

She cant remember when the internet died exactly.
At some point, she dont know if it was yesterday or another day, the computer asked her to re-install the system and then she clicked "OK". She cant remember if the internet died after that, but she knows she was playing games on Facebook yesterday morning, and that the internet didnt work in the afternoon.

I personally believe its the "internet card" (dont know what it's called in english) is broken, or that she has clicked something she shouldn't have clicked.

Here is what I've already tried:
- Turning the router on and off
- Plugging the computer to a ethernet cable = still no internet
- Following a suggestion from this forum about turning the internet to Power Save Mode off (and on)
- Called her internet company, nothing was wrong (my computer, my iphone and her phone is connected to the internet)
- Setting the computer to "secure mode with internet"
- .... And turning the computer on and off
(- Her Suggestion: Turning the dishwasher off, as it "for sure had something to do with it". Did not work.)

I/we really really hope someone want to help with this. I know questions like this has been answered already all over the place, but Im lost and dont know what to look for anymore.
And she is afraid her facebook games will be deleted if she doesnt play it soon...

Thank you very much in advance!