Hello, you need to offer a little more info as it is difficult to help when people dont know what version of mint you are using, the desktop environment (cinnamon/mate etc) or any of your computer's spec's, there are different ways to solve the same problem in differerent desktops, just like windows, there isn't a universal fix it so if you can post some more info somebody will be able to help . . . .. . . .
Lenovo ThinkPad T61 Linux Mint 12 Lisa & Mint 14 Nadia (on different HDDs) 2x Intel Core 2 Duo CPU T7500 @ 2.2GHz/ Kernel Linux 3.0.0-12-generic (i686) Desktop Environment - Cinammon 1.6/ Intel GM965/GL960 Graphics Controller.