Hello again!

I've made it!

To reset it you must do the next steps:

1. Download drivers and CWM from this topic 

2. Download Android Debug Tools (search in Google).

3. Boot the tablet into fastboot mode (Turn it off, hold Volume- and Power buttons, it will blink white LED and make one long buzz, wait 5-10 seconds and release the buttons).

4. Connect the tablet to the PC and install drivers.

5. Place CWM file in the folder where fastboot.exe from Android Debug Tools lies and rename it to "recovery.img".

6. Run command prompt and run next command "fastboot devices". You should see 1 line consisting ""serial number" fastboot"

7. Run "fastboot boot recovery.img". The tablet should start CWM recovery.

8. Erase cache and user data through CWM Recovery and then select "Reboot now" menu item.

globula_neagra said
you can do it easier by going directly to fastboot and use the command
fastboot -w
which will erase the cache and data.

I have tried to do so several times, but it did not helped.

The command line showed that user data and cache was erased, but when I rebooted the tablet, the password was still intact.

Only the sequence written above helped me to make a hard reset on my tablet.