Hi Pauli,
This issue may occur due to damaged wireless network drivers or due to incorrect wireless network settings.
**Method 1:**I would suggest you to try the steps in the article and check if it helps.
Note: Try all the steps except troubleshooter.
Wired and wireless network problems
Method 2:
If the issue persists, I would suggest you to install latest Wi-Fi driver from the computer manufacturer website and check if it helps. If Windows 8.1 drivers are not available then install Windows 8 drivers in compatibility mode.
To install the Wireless network driver in compatibility mode, I would suggest you to follow these steps.
a. Download the latest Wireless network driverfor Windows 8 from the manufacturer’s website and save it on your local disk.
b. Right-click on the setup file of the driver and select “Properties”.
c. Select “Compatibility” Tab.
d. Place a check mark next to “Run this program in Compatibility mode” and select Windows 8 from the drop down list.
e. Let the driver install and then check the functionality.
Hope this information helps. Reply to the post with updated status of the issue to assist you further.