Fix internet connection problems?

I bought a new computer which seems to have an EXTREMELY weak internet connection. It does not connect with my modem or with the amplifier of the modem. All other devices in my house (including my old computer, laptop, and cell phone) have no problems.

When I connect the computer to my cell phone hotspot, the connection is reasonably good as long as the cell phone is right next to the computer. As soon as I walk away with it, the connection is gone again - even if I stay in the same room.

Can someone help me out? Is there anything i can do?

Turned off the amplifier. Had the same problem recently. It was my repeater's fault. As soon as I switched it off, the connection was great

Turned the amplifier on and off, even moved it to my room, didn't change anything.

What kind of pc is it? If it is a tower, it could be that it has a weak WLAN module. In that case, you should buy such a WLAN stick. If it's a relatively new notebook or something, I can't imagine that it's because of it.

You don't actually need a signal amplifier, the Fritzbox has a range of 20 m. A signal amplifier, e.g. Repeater or TP-Link, is only worthwhile when the receiver is further away.

I would call the provider and have the Internet connection checked. Turn everything off and just turn on the router, thereby dialing in again, waiting until it is fully operational. Then boot up the PC and clean it up. The next step: Check all drivers in the device manager, update if necessary.

If all else fails, contact a PC specialist.