I've recently had the same problem, however I think you may find that the information I have posted on this forum may help you.
The information is here : http://linuxmint.com/forum/viewtopic.php?f=53&t=10086
I've not had to download or install any extra drivers to get the RalinkTech USB Wifi device working, it's just a simple
matter of changing one file as detailed in my article above.
Hope this helps, if not feel free to come back to me.
How would I be able to install a driver for a wireless usb adapter so can get on the internet.
Here is the website of the company who makes the wireless adapter. I have downloaded the drivers but don't know how to install them.http://www.ralinktech.com/ralink/Home/S ... Linux.html
Thanks for all your help!