About switching off Wi-Fi, and about opening the case

[nmn]

Hi,
I need to switch off Wi-Fi - to be sure of have done it, in BIOS or in hardware. Is it possible? I prefer to do it in hard - if it works via USB (as a USB WiFi adapter, as I suppose), to disconnect it inside the case - is it possible?
And, if I open the case - I know that I lose my warranty by it - are there any sensitive parts that may become immediately broken or out of order, something like thermal grease between CPU and case cover? Or it may be opened (with loss of warranty), just closed again, and all will work?
Sincerely yours,
Mikhail Nikulin.

[irads]

Warning: the steps listed below void the warranty
If you know what you are doing, the risk of breaking anything is low.
WiFi is USB and is on the top side of PCB.
Be careful of ESD and make sure the thermal tape on CPU and IOH has good contact. You can peel it off - massage it to a thick blob and apply it again.