F5 Player select not working

Hi,

I seem to have a new problem whereby the F5 key (to select a player) isn't working. The rest of the F keys work. I have run tests on the keyboard using software in the Windows environment and the F5 key press works fine. If I am a mage, I cant target the person whom is assigned to that key.

I am using Windows 7 64bit Pro with a Microsoft Wireless Keyboard 800.

Thanks.