Eu encontrei esta informação aqui nos fóruns de suporte da Lenovo :
Disabling the "Browser Back Key":
Get the ThinkVantage Keyboard Customizer:
http://support.lenovo.com/de/de/downloads/ds000695
Install it:
Note, after downloading/running the exe it does not install the app yet, it just extracts it. After the app gets extracted, go to the folder where you have it and run the setup. Then, reboot your laptop.
Disable the Browser Back Key:
Go to your Start menu,
ThinkVantage,
Keyboard Customizer Utility,
Key sensitivity tab,
uncheck Enable Browser Keys