Hi Bogdan,
My installation did not have a service for UiRobot installed so I could not re-start the service because it does not exist.
Summary of installation: Windows Server 2008 R2 Standard. UiPath 18.1.3. UiPath was installed through Administrator console. UiPath Studio runs well, but, need to click on UiRobot.exe to run the robot tray.
I followed this link to install the UiRobot service. Service is now present but it does not run. It gives error 14001 side-by-side configuration problem after a server re-start.