No internet after reinstalling Windows 7

Hello,

I just reinstalled Windows 7 Home Premium on my desktop PC. But, catastrophe, I no longer have an internet connection! My PC does not detect my router anymore.
This is indeed a problem stemming from the reinstallation because I had no issues before (wired internet connection) and I can still connect to my wired internet from other computers.
So in the taskbar of my desktop PC, when I hover the cursor over the connection icon, a small phrase pops up:
“Not connected - No connections are available”
I click on the icon and then on: “troubleshoot problems”
And the Windows network diagnostics gives me the following message:
“Install a driver for your network adapter.
Windows did not detect a properly installed network adapter. If you have a network adapter, you need to reinstall the driver.”

In startup, I go to “computer”,
then “system properties”,
and “device manager”
There I notice that in “Other devices” I have a yellow triangle with an exclamation point in front of:
_Ethernet Controller

When I click on this controller, the “device status” box indicates that:
“The drivers for this device are not installed. (Code 28)
To find a driver for this device, click on Update Driver”
But I cannot perform the update.
In the “resources” tab it states: “This device is not using any resources because it has a problem.

My computer is a LDLC PC7 Forcer https://www.ldlc.com/fr-be/fiche/PB00117118.html purchased from LDLC. (I actually chose this computer on the advice of one of the contributors to this forum
My internet provider is Télénet (I am in Belgium).

Thank you in advance for your help!