SOLVED -- Function Key not working

[hardy]

Pressing the F5 Function Key (Copy) does not work. Pressing F2, F6 and F7 will execute the proper command. In another File Commander (Turbonavigator), F5 is working properly. I don't remember having changed the MC configuration recently. I have assigned a button to F5 in the Button Panel and it is working on mouse click. Thank you for your attention.

[hardy]

As Matthias had suggested, a complete shut-down and re-start of the Windows 7 operating system brought the functionality of the Function Key within MC back. The functionality seems to get lost during hibernation or stand-by of Windows. Seems to be a peculiarity of MC.