virtualbox.org

I'm using Windows 7 in a virtualbox session under MAC OS x Lion.
Function key are not working as expected even if I press fn+function key (e.g. F4)
How can I obtain F1-F2 functionality in windows?

For normal F1-F12 functionality, you have to disable the media keys on your Mac. Open System Preferences and go to Keyboard. There you have to disable it. Then the media keys are accessed through Fn+Fx, instead of directly pressing Fx. They will be send properly to the VM now (F1 would call upon help in Windows, instead of doing nothing).