Most notebooks have several hardware components installed that are not used by the user. A notebook with WLAN and network card for instance and a user that only uses the WLAN to connect to a network and the Internet. Every component installed is using battery and it is a wise step to disable those components that are not used – ever.
The Wlan – Network Card example was just one possibility. Many notebooks have a card reader, DVD drive, webcams and V.90 Modems among other components. My notebook for example offers both Wlan and LAN access and I have disabled the network card which had the positive side effect that it reduced the boot time of my notebook.
I disabled the card reader and the internal modem as well because I never use those components. The DVD drive is disabled as well most of the time because I rarely use it. I don’t have the necessary test equipment to test the battery usage before and after disabling the components but I can verify that the boot process into Windows is faster than before.
Related posts:
- Notebook Hardware Control
- Useful Notebook Tools
- Windows Vista Notebook Battery Saver
- Install the latest Nvidia Drivers on your Notebook
- Notebook Battery Monitor
- Display Notebook Battery Status
- Track the location of your notebook with Adeona
- Sorry you cannot use that battery because it is not made by us !

By disabling, I take it you mean from the device manager – perhaps you could make it clearer in your post.
Some can also be disabled in the Bios but generally I meant the Device Manager yes.