Disabling hardware WITHIN the BIOS?

I have an Inspiron 6000, I see that you can disable hardware from within the BIOS such as the INTERNAL NIC (10/100 ethernet), 56K modem, MiniPCI slot (WiFI card slot), etc. If you are not using hardware such as a dial up modem or the internal NIC (10/100) card, etc, is it ok to disable them in the BIOS? I mean why waste power on battery for hardware slots your not even using? I just wanted to know if this was OK to do, or would disabling stuff cause problems with the system?

Also, I'm getting a PC Card WiFI card because I'm tired of the WiFI light issues on the Inspiron 6000's not working correctly. So I wanted to know if it's OK if I disable this too (the Mini PCI card slot) from within the BIOS since I won't be using the slot? I'm going to just sell the card, I'm tired of the light not working correctly on the keyboard.

Thanks.