No internet can be caused by a number of things.
These can sometimes be resolved by some simple checks.

If all the computer’s in your home are not receiving the internet:  Reboot your router, (turn off your modem and power it on again), this can be done by pulling out the power lead on the modem.  If this fails call your internet service provider. If the service provider informs you that everything is fine from their end, then you will need an experienced engineer to investigate the problem.

Firewall can sometimes block internet traffic to your web browser, so a check on this would also be advisable.

If you have more than one computer at home and one connects and the other does not, the problem lies with the computer failing to connect.  In this instance it will be unlikely that your internet provider will be able to help.Sometimes windows or the internet browser (internet explorer, Firefox, Google chrome) becomes
corrupted and requires a clean installation of windows; see hard drive formatting.
If reinstallation of the internet browser fails to work, this means that the problem is within the configuration and windows.