Sometimes, but too often, my keyboard acts funny, as if the Windows key is also pressed. For example: when I type e in a text editor, no e appears but instead a new File Explorer window is opened, as if I had typed the Windows-E keyboard shortcut. Similary, typing m shows the desktop after minimizing all windows, like Windows-M. This way, I found out that practically every letter of the alphabet has a Windows shortcut.
My system is Windows 7, with Virtual PC windows XP. I do most work in XP, and the problem only happens in Win7. Then, the only way to google for solutions and to write this question is to use XP.
This also excludes any physical problem with the keyboard. But to be 110 percent sure, I tried adding a brand new Lenovo usb keyboard; result: same problem on both keyboards.
The system manager here has never seen something like this, so I hope that anybody on the Internet might have a clue. Many thanks in advance!