If you are not getting the link to the system , even your Router , switches and ISP are all working fine, then how will you troubleshoot this issue ?

First ping it,

check ip config

if everything is fine then definitely there will be some issue with cables, remove and insert cables once again, restart it ..

Initially try the PING command, if not

check if the wiring is fine at the system, if not,

check for the wiring at the switch end, if not,

check if the lights at the both ends of a crimping tool are glowing sequentially(1-8) if not,

try to insert the cable in another empty slot.

I'm sure one of this will work out just fine

Mostly L-1 problem, physically check and then check our gate way and IP address.

because in that question mentioned that router and switch and ISP working fine but only our system is not accessing those devices so we should check in our system ip address and cable which is connected to the switch port.

Surely problem in connection between system and switch or router and switch.

First ping on both end and re-insert or replace the physical cable 

1 - First use the ping  Command .

2- check ip config .. if everything is fine then .

3- Check The  cables ...

4- restart.

first check ip config then the cable which connect between the ISP & Router

First physically check NIC if there LEDs are indicating connectivity, also make sure that it is not disabled.

Next, check IP Settings of your PC, if it is set as dynamic, It will be able to obtain IP Address from the router or an existing DHCP server, if it statically assigned, make sure that IP address is at the same subnet with your router, and a default gateway is defined.

We can also console to the router to check if the interfaces are well defined, and in the correct subnets, and check if there are valid routes going to the ISP.

First Ping it, if it does not work, check the ISP links and then remove cables and insert it again and restart it.

As the question states,if layer 2 and layer 3 devices are working fine then clearly issue is with either cable that which runs from system to switch or may be the NIC card of the system is faulty.

if all router, switches, isp are fine ,then u have to check cabling and also the cable is crimped properly by checking the end of RJ45 connector ,if it is ok ,then check the IP Address of the system whether the System IP is in the same network or not.

Check from ordering operation entrances used then make sure to send Ping

If the problem continues to make sure the cables