Wi-Fi does not work properly with computer and laptop. What can it be?

Al
1

With the mobile phones everything works, only with the PC and laptop also the television can be difficult to connect with the Wlan. It's always a movie! That's been the case for 2 weeks, why can this be? And if it works the connection will be bad afterwards. I also have some paranoia that the police are watching me because some time ago I sent a death threat to a person that was specific and repeated, that person also threatened to report me to the police. I said as long as the conversation between us does not arise in which she apologizes, I accept the ad. The story is irrelevant (my death threat is of course nothing!)

Maybe it's also because the police are spying on my surfing activities? Someone said lately synonymous something wrong with your Wi-Fi, there must be someone else connected.

Gr

Unfortunately, one knows too little about your WLAN infrastructure to give the exact information.
For my case, I have a "Fritz Box", in whose menu you can see which users are logged in and "record".

In addition, I have changed the encryption (no default, different password) and assign fixed IP addresses. Then I activated the menu item "Restrict WLAN access to known devices (MAC address filter)".
Thus, one would have done almost everything to make the penetration "almost" impossible.

It would be important if the "field strength" in the apartment is sufficient to supply the equipment.