@Smeaol I'm not an expert.
If it wasn't problem there before, check the IP addresses of Advanced - network - lan settings, try copy from me. 

Is the ip address in windows perhaps set to "static" so it is fighting with a busy address?  Unrelated to your problem, do you use voip service?

  @tomycrosound Thank you very much for your help

Everything was the same except Default Gateway which was 0.0.0.0 . I put 192.168.1.1 and it did not fix the problem. Still It took 15 minutes to activate the Ethernet, though the Ethernet light on the modem is green.

  @Smeaol Probably some nonsense.. Is dhcp enabled on the laptop for IPv4? I would try downloading again the driver for the network card on the laptop, try another LAN port on the router and - another LAN cable!

Is there any information in the log file in the router? 
 

  @tomycrosound Thanks, my previous modem is still with me and I can have ethernet connection with it instantly on log in with my computers. Cable is same also. There is an issue with modem. 

After ethernet connection is established in Archer modem, if I put the computer into sleep and wake it up, ethernet connection is there instantly.

When I put the computer into sleep at night, Archer modem forgets its ethernet process somehow, when I wake the computer in the morning the ethernet process is boot up again in 15 minutes. Not sure what is making the modem behave this way.

  @Smeaol Does it connect to wifi devices quickly? Try reinstalling the network card drivers, and check if dhcp is turned off in the laptop and a static address is set.

The PC is looking for an IP address for too long, probably something is in sync with the old router; maybe the setup is different and the ip address in the laptop is static which does not correspond to the new router or is busy.

1. **Control Panel**  
2. **Network and Sharing Center**  
3. **Change adapter settings**  
4. Right-click on your network adapter (e.g., Ethernet) and select **Properties**  
5. Select **Internet Protocol Version 4 (TCP/IPv4)** and click **Properties**  
6. Choose **Obtain an IP address automatically** and **Obtain DNS server address automatically**  
7. Click **OK** and then **Close**

  @Smeaol this happens to me if I try to plug it into the first port on the left (with vx1800v facing forward). I've found it works better if plugged into the second or third for some reason. Couldn't explain why though :)