I encountered the strangest issue and I hope that someone out there can help me. I bought Vaio Z Series in April 2010. Just 3 months, the letter w appeared non-stop intermittenly. I have send it back to Sony service centre and just got it back 2 days ago. They have changed the keyboard and reformate the OS Window 7. Today it started again. It will not be so frequent initially but it will get more and more frequent and prolonged timing. What exactly is the problem? Seem that even Vaio is unable to indentify?!