Check that your BIOS from your compu have good time for that to turn it once you enter the "setup", many machines say "press (key) to setup" or similar, commonly is F2 or supr but several may differ a see who is entering Czech well the time and date, otherwise adjust it, save your changes and reboot.
Once you check in Windows when you're that good as far if not properly adjust it too, right there after you upgrade to "Internet time" and you disable "Automatically synchronize with internet time server.
That should solve your problem, I recommend you also install google chrome as a browser, Greetings!