Apologies for the delay getting back to you.
Try pressing the Fn and the Home key down at the same time.
Good decision not going any further with the driver updates from TweakBit, there are some reputable sites such as DriverMax but in the main you will be asked to pay a fee for drivers that you do not need and that are readily available from the computer manufacturer which in this instance is Lenovo, download page here download to a USB thumb drive or burn to disk for safe keeping.
Did you not get a driver and utilities disk when you purchased the notebook.
As an asides, the Windows 8.1 update was also available direct from Lenovo, the information made available also included how installing the update could affect your computer, details here