Hi Krishna, Thanks very much for your quick reply. However, non of the suggestions are working for me. The start button is not responding to any mouse clicks. Not even the one on my keyboard. I have seen a double arrow on the taks bar. When I click it, it shows me a list of the applications on my pc. However, when I select an application and right click, I get a short menu with "pin to stsart" and "pin to Taskbar". When I select any of the two, the icon is always pinned on the task bar. The start screen is never shown. I see just a blue screen.
Please let have any other suggestion.