I use Windows 7 in a Bootcamp partition on my iMac. I always check the option "Use all F1, F2, etc. keys as standard function keys", and when it's checked, everything works great.

But recently, something switches this setting back to 'unchecked' every few minutes. I constantly have to open the Boot Camp Control Panel, uncheck the checkbox, check it again and click on 'Apply'. And five minutes later, the F2 key again controls the brightness of the screen and not the renaming of files in Explorer.

This is driving me mad. What could be the cause of this? Is there a keystroke to switch this feature?