avr-g++: error: device-specs/specs-atmega328p: No such file or directory

Hi.
I started my adventure with Arduino Uno and at the beginning I've get the error which stopped me.
I've installed version 1.8.9 on my Win7 and every time when I want to compile the Blink example I am getting error:
avr-g++: error: device-specs/specs-atmega328p: No such file or directory
I choosed in menu Tools board Arduino/Genuino Uno and port COM9.
I've tried install an older version 1.0.6 but I get an error:
arduino avr-g++: createprocess: no such file or directory
I turned off my antivirus's firewalls and I am starting Arduino as a administrator but it didn't helped at all.
I am using Java Version 8 Update 21 (build 1.8.0_211-b12).
Also I tried to add to file platform.txt (C:\Arduino\hardware\arduino\avr) a line:
compiler.cpp.extra_flags= -v -B C:\Arduino\hardware\tools\avr\lib\gcc\avr\5.4.0\device-specs.
This idea I found on some forum but it didn't also helped.
If someone can write me down what else solution can I try I will appreciate that.

Try uninstalling 1.8.9 and then installing it again.

I've tried a uninstall and install again few times but it didn't helped.

This sort of error could be caused by your antivirus software. Try TEMPORARILY disabling your antivirus for a single compilation to see if the problem goes away, then turn the antivirus back on. If the problem doesn't occur with the antivirus off you will need to adjust the settings of your antivirus to whitelist the appropriate file, folder, or process so it doesn't interfere with compilation.