I recently installed a new keyboard and mouse, a Microsoft Wireless 5000. The first thing I noticed was the scroll wheel on the mouse seemed to have a mind of its own. But most annoying was that the scroll wheel did not work at all with some programmes, namely Picasa, a programme I use quite frequently. After fiddling with the settings I still could not solve the problem. There were lots of posts on the net about this problem but no solutions. I eventually came across the suggestion of changing the mouse to a different type in the configuration. I chose "Standard Wireless Optical Mouse", see the screen grab below. hen go to the "Wheel Button" drop down menu and choose auto-scroll. The mouse and scroll button now works perfectly with Picasa.