Laptop Network Port not working

Dear All,
Please help me to judge this issue.
I have problem with my laptop network port.
When i plug Network cable from Modem to my Laptop Network port, i always get No internet connection
and when i tried other laptop and the problem still persist..
At first time i thought maybe problem with Internet but last time, when i tried to plug network cable from Modem to Desktop network port, it working fine..

So Please let me know what is the problem of these two laptops?
One of my frequently laptop is specs:
-Windows 7 x64
-CPU Intel Core i7 4th
-RAM 32 GB
-Hard Disk drive 1 TB
-AVG internet security
-Malware byte..

P.S: Even i treid to uninstall AVG or Malware byte but not help.

Please help me.

Dear Cyberman,
THanks for your time.
This problem with my two laptops when i plug network cable from Modem to Laptops network ports, not working.
But when i plug cable network from Modem to my desktop PC, Internet is working.

I have changed ethernet cable but still not help with my two laptops.
The modem is make Motorola
Best regards,

Dear CyberMan,
That modem is belong to my ISP and right now i am using internet through WIFI configured router from that Modem.. But i don't know why my two laptop network port not working when i conected direct from Model.

I already registered MAC of that modem to my ISP and the make is Motorola.

This is wrong with my two laptop ethernet port?
Do you still any ways to try to fix this problem?

Hello there, I am also facing similar problem with my user laptop... when they are connecting the laptop through LAN cable its not connecting. with that same LAN cable, when i am connecting other user Laptop its connecting. this problem is having only for two or three users and rest of the users can connect to the LAN easily. if anybody can tell me the solution for this issue..it would be great help....thank you.