hi to all from Mally;Ok i just upgraded to win 10 from win 7 two days ago;it was a longish process but all went well until yesterday when the bottom left start button wouldn,t open.After reading a lot of comments from various forums I have come to the conclusion that cleaning and optimizing the registry has caused this.So please be aware of programs like cc cleaner and other registry cleaners.I have re installed windows 10 again and the start menu opens with no problems.You can download win 10 from microsoft webpage using media.exe for 32bit and 64 bit.Let me know if this has been any help. regards Mally