Wifi switch on Toshiba laptop does not work. im sure its not software. will an external wifi device work?

note: i am a mere computer user. like a car driver, you open up the hood and its like another planet. so i may not be using the right terminology. be grateful for your tolerance. please feel free to ask what i mean by this or that

A fairly good independent computer repairman found my hardrive startup or boot "sector" was bad. We got a cheap used hardrive. He even had a portable diagnostice tool to test it from the person we bought it from. When i watched him put my laptop back together i noticed he saw some piece of plastic he thought was merely a half broken piece which merely had something to snap computer together along with the screws.

Well i think he may have broken off something had something to do with the wifi switch for the internal wifi hardware. he also took out a small flat thing with a chip in it he said was only for 56kbps over telephone line, forgot what you call it.

would not the easiest thing to do is just buy an external usb wifi device or one of those older bigger slide in slot things?