I can't connect to the internet; guide causes and solutions

Have Internet connection problems, especially in British due to the weakness (and scarcity) of telecommunication infrastructures, it is quite frequent and, very often, the cause lies in the line managed by the ADSL operator.
But before calling the call center to report a problem on the internet, it is necessary do all the tests home for check if the cause depends on us, from our computer or router and, therefore, if it can be solved without having to wait for the intervention of the technician.
In this summary article, we see, in a synthetic but complete way, all the control operations to be done when we can no longer connect to the Internet, to identify and correct errors on the network and on web browsing.

We can divide the solutions in three groups, one for operating system problems, computer-related solutions, and solutions for any network and router problems.
When the internet does not work, in fact, you have to try to understand where the problem lies: for example it may happen that I cannot browse the internet by opening Chrome or Firefox while a program like Skype works, or that one computer connects well while another does not. despite being the same network.
I must point out that the order of the operations to be done to restore the internet and of the solutions is not chronological so it is advisable to print this guide and read it all before proceeding.

1) Software problems on the operating system and browser
First of all check the network icon near the clock which, if the connection were limited or with errors, would have a yellow triangle while if there was one Red X, the connection would be absent.

If the icon is normal and you are unable to navigate, then the problem lies with the web browser that has some wrong configuration, possibly due to malware.
What you need to check right away is that a proxy that hijacks the navigation making it slow or not possible.
In each browser, be it Chrome, Firefox or Internet Explorer, open the settings and check the Proxy options which, unless specifically required, must be configured on "no proxy".
After this, to solve any web browsing problem, it is better to first do a virus check on Chrome, Firefox and Internet Explorer also useful for checking if there are malicious extensions and if the hosts file is clean.
If there is something wrong and you can't figure out what, do a reset all browsers to default settings.

If the network icon has a yellow exclamation mark (then the computer is connected to the network, but not to the internet) or a red cross (the computer is disconnected), you need to check the system settings.
Right click on the network icon above to open the Network and Sharing Center to do an automatic diagnosis which should tell us why you are unable to connect your computer.
From the network connections screen, left click on Modify impostazioni scheda and then right-click on the network card used and active (check that it is not disabled) to diagnose and detect problems.
The "Change adapter settings" screen can also be opened from the Start menu, by going to Run and sending the command ncpa.cpl.
If you are not satisfied, you can check the connection problems with the Google Chrome browser.
From the network cards screen, right-click on the card used, open the properties, then scroll down and select TCP / IPv4, click on Properties and make sure that all fields are empty and that the options are enabled " Obtain automatically ... ".
This tells the network card to obtain the IP address from a DHCP server.
Then click on OK and, after a short time, right-click again on the network card to go into the details and verify that an IP address has actually been assigned (which must not begin with the number 169), a DNS address and a gateway address.

If nothing changes or if there is no outlier, try le solutions to errors on sockets, LSPs, and TCP / IP Stacks that cause limited or no connectivity, as already explained in the past.
Without being an expert, it's just a matter of running an automatic program that resets the parameters and restores the network.

If a solution has not yet been found, another attempt is to clear the DNS cache, as explained in the guide on solutions if DNS is not responding which is a very common problem.

2) Computer Problems
The internet may not work due to a hardware problem.
It is usually easy to understand if you are unable to connect because of the computer, because just try another PC or smartphone and see if it works.
The network icon can be with a yellow exclamation point or a red cross above, which really means "device disconnected".
In this case the solutions are the most obvious:
- Check that the cable is well connected if it is a wired connection.
- Try a different cable.
- Check that the network card located behind the desktop PC, the one with the antenna or the Ethernet socket, has been properly fixed.
If it moves with your hand, you will need to open the computer and secure it securely.
- Check that the wireless signal reception is good and not poor.
- Check that the wifi radio is on (on some laptops there is also a physical switch, on others you can press a combination of keys such as Fn + F5 or there is a network management program visible from the icon next to the 'clock).
- Check that a firewall or antivirus blocking any incoming connection is not active.
Then try turning them off to see if everything goes back to normal.
- A connection problem with the router.

An operation that can help is that of reset the network card.
enable and disable a network card just press on its icon with the right button from the "change board settings" window (the one that opens with the ncpa.cpl command as seen above).
Please note that if you are using two or more network cards, for example an Ethernet and a Wifi, it may be necessary to disable one of the two.
To reset a network card instead you can try completely uninstall the card and reinstall it.
This is done from the Device Manager utility (found in the Control Panel), in the Network Adapters section.
Right-click on the network card used for Internet access and click Uninstall.
Restart your computer and notice that Windows automatically reinstalls the card with default parameters.

That is unlikely to be a solution, but if the computer is old, it may be necessary update the network card drivers.
To facilitate the operation, we have seen, in another article, an automatic tool to download the updated network card driver on Windows PCs.

2) Problems with the router
If the computer is fine and above all if all the PCs in the house and even cell phones and tablets are unable to connect to the internet, surely the problem depends either on the modem / router or on our ADSL provider.
Before calling the assistance of Telecom, Fastweb, Libero or any other telephone and internet provider, try to restart the router / modem.
This is a simple but very effective solution to solving the problem.
Then turn off the modem / router using the button on the back, wait a minute and turn it back on to see if it resumes.
If you can't find the button, try unplugging and reattaching it.

Note: Before doing any other operation on the router, you need to know if it is owned by us or if it has been provided by the provider.
In this second case it may be that you cannot even access its settings and that any manual operation worsens the situation.

If restarting the modem / router doesn't work, try a reset the router, which will erase all customized settings, including network login passwords.
The reset button is usually a small hole in the back of the router that you have to press, with a pen, for a certain period of time which can be around 30 seconds.

For all other tests and settings to be checked and possibly modified, refer to the article on solutions wifi connection problems and router.

After all these checks it is worth calling the assistance service of the ADSL provider who will restore the line after one or more days.
The big advantage, after reading this article, will be to be able to talk to the au pair operator, showing competence, without appearing naive and without wasting time with the basic solutions, which we have already tried on our own.

I can't connect to the internet; guide causes and solutions

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