internet showing disconnected but isnt

click on the icon and hit open Network & Sharing Center

Here you will see a picture at the top of the screen which will work like this.

PC - Router/Modem - Internet

Check where the problem persists between Router/Modem & Internet or PC & Router/Modem.
If the problem is between Router/Modem and Internet contact your Internet Service Provider (ISP)

Here are some simple fixes if it is PC to Router/Modem.
1. Turn Router off, Turn PC Off wait 10mins then turn both back on.
2. Try a different Ethernet Cable
3. Ensure that your network driver is working (Below)
4. Restart your Network adapter (Below)

3.
Click Start
Right Click My Computer
Click Manage

You are now in the Computer manager on the left Click Device Manager

Check for any problems (these will be devices with a yellow exclamation mark next to them) these might be found under Network Adapters.

4.
click your network Icon on the bottom right of the screen and open the Network & Sharing Center
now click Manage Network Connections

Here locate your network adapter click it, push Disable this Network Device above - followed by Enable this Network Device. Therefore Restarting the Network adapter.