if incorrect time then I can not use internet properly

Yes - encrypted connections, such as SSL, use certificates which have an issue day and expiry date. If the time on your device is wrong, then it's possible the certificate won't have been issued.

some encrypted connections require the time to be no more than a few minutes different.

On Windows, you.can create a scheduled task which forces a time update:

https://www.pretentiousname.com/timesync/

If a website presents a certificate with a validity period that doesn't match the current value of your system's clock then your internet Browser can't verify that the connection is secure and therefore opens a "Your connection is not secure" error page.

More Details:
https://support.mozilla.org/en-US/kb/troubleshoot-time-errors-secure-websites

An explanation from Mozilla Support:
Certificates used by websites which are considered to be secure (their URL begins with "https://") are only issued for a certain period of time. If a website presents a certificate with a validity period that doesn't match the current value of your system's clock, Firefox can't verify that the connection is secure and therefore opens a "Your connection is not secure" error page. Some methods to validate that a certificate hasn't been revoked also depend on your system and the webserver being set to the correct time.

Such issues can be fixed by the correct setting of the date, time and time zone on your system.

If the website allows it, you can add an exception to be able to visit the site, despite the fact that the certificate is not trusted by default:
- On the warning page, click Advanced.
- Click Add Exception…. The Add Security Exception dialog will appear.
- Read the text describing the problems with the website. You can click View… to closer inspect the untrusted certificate.
- Click Confirm Security Exception if you are sure you want to trust the site.

More info here.

Sorry Ramin. It took me a while to get the post above together so I missed your post.

is the date/time incorrect?  then you may havea low bios battery - it should read 3V min

while it may not matter to you if the date/time on your computer is correct, it matters to the internet, and to the operating system.

as nobus says, if the CMOS battery is low, then the date/time will be reset when the motherboard loses power (or when you reboot)

as RobMobility has said, you can create a scheduled task to set the time by an internet time server (there are also small apps you can get that will do it for you - like this one - http://download.cnet.com/Atomic-Clock-Sync/3000-18512_4-14844.html)

the date (and to a lesser extent, the time) of your computer needs to be accurate, otherwise internet sites will not work properly (as you have found out).

Check the link below and set the time sync with internet time.


https://www.youtube.com/watch?v=eIEWqptLLmk

So I have to manually approve every certificate or fix time?

did you check the bios battery - as i asked you ?
post results plse

correction - the battery should be a CR2032 not a CR232 (typo)

I think this answer was the best because it explains fix and why error exists. It is necessary that time matches certificate for my safety.

Thanks.