Hi Fernando,
I merged both of your threads to save on confusion please do not double post.
Please post the make and model of your machine.
Can you remember if anything was installed prior to the issue starting?
Have you ran a malware scan? If not and currently have access to the net download, install and run Malwarebytes:
Anti-Malware for your home and for your business
When the issue occurs and you cannot connect see if you can take a look at the Device manager and if any yellow question marks have appeared.
Have you considered trying 'System restore' and setting the machine back to before the problem started?
File scans
Right click on the Start menu icon and from the revealed list choose 'admin command prompt'. Type:
sfc /scannow
press enter and await results
In the same command prompt and after the above scan has finished type:
dism /online /cleanup-image /restorehealth
Press enter and await results (longer this time).
If the first scan found files it could not repair but the second scan is successful, run the first scan again using the same command prompt box and this time it should repair the files found.
Did you see any blue screens? if so please check this thread:
How to ask for help with a BSOD problem