F1-F12 keys have special features printed on each key, but when using the standard F1-F12 functions without any of the special features, then press the Fn key plus F1-F12.
The above symptom may occur on the following systems:
Microsoft Windows 7
Lenovo Ultraslim Plus Wireless Keyboard and Mouse
Lenovo Ultraslim Plus Wireless Keyboard and Mouse - Service parts
If your system is not the Lenovo preloaded image or from the R-DVD recovery, you may still need to download the following software, then install this package.
Lenovo Ultraslim Plus Wireless Keyboard and Mouse for Windows 7 (32-bit and 64-bit), Vista (32-bit and 64-bit), XP - ThinkCentre Edge 91z, Edge 71z