You have to tell us more facts.
The minimum is exactly which Mint you have - which version and which edition (main or any of the CEs)
We also need to know a bit about all your hardware.
Run " lspci " in a terminal and post here (to avoid misunderstanding - the first character is a minor L and you copy by marking with the mouse and then right click)
Some wifi and possibly built in sound can be connected to USB even if they are internal - if you suspect you have one of these run " lsusb " in a terminal.
Also tell us if this is using mint4win or not, quite important
Don't fix it if it ain't broken, don't break it if you can't fix it