I have mint 17.2, wifi worked fine for awhile but suddenly stopped. I replaced the mini wifi card inside computer with no results?
I'm with dcrunkilton. ...
I'm with dcrunkilton.
In particular, if a late-model version of a Live CD and/or a USB Wifi dongle would be the tools I'd troubleshoot with. If you provided the make/model of the laptop and the mini-wifi card, the particular driver/firmware required could be identified.
I once had a problem with the internal wifi card that was so terrible that I...
I once had a problem with the internal wifi card that was so terrible that I had to use an external usb wifi dongle. Here is how bad it was: The wifi failed and I tried everything, even falling back to an earlier distribution with no improvment. I bought a new internal wifi card; no improvement. I concluded that the socket for the wifi card was bad. By that I mean either the physical socket or the electronic interface was defective. In general, sockets are a source of hardware failures: wifi and memory sockets on both laptops and desktops. So, go for an external usb wifi dongle. Depending on your distribution, you may need to install non-free firmware for the chipset in your usb dongle. Since your internal wifi once worked, you already know how to deal with that. "lsusb" without the quotes will give you info on the chipset. For debian, ubuntu, mint: firmware-realtek, firmware-ralink are some firmware examples.
One diagnostic technique that you might try first on your internal wifi is to boot up from a "Live CD" of your current distribution, or a different one. Test the internal wifi.
Another remote possibility that I have experienced is a software regression. An update to my distribution killed my wifi. Maybe the drivers were deemed to not meet the legal requirements of the distribution, and removed. Or maybe an inadvertent bug was introduced.