Serious problems

[Lantesh]

Go into terminal. Type this: sudo displayconfig-gtk . Enter your password. A nice GUI will open and you can change your settings.

[Lantesh]

Try booting into recovery mode (second option on Grub menu). This should get you into a basic vesa environment. From here you can make any driver or resolution changes you need. Sorry I can't help you more because I don't know anything about your system. If you give more info more knowledgeable people here like Fred will probably respond.

[Husse]

Thank you for your interest in Mint
To help you solve your problem we need to know exactly what Mint you use.
By that I mean version (like Celena or Daryna or numerical if you prefer) and edition (main = Gnome, KDE or some of the Community Editions like xfce or fluxbox or the mini edition)
We also need possible error messages, exactly as they appear
We also need information about your hardware. You can obtain that by running
lspci
in a terminal
If it is something connected to USB you run
lsusb
and similarly for other 'buses' like pcmcia....
To copy from a terminal mark (with the mouse) and right click
Then paste into a code box (it does not use as much space then)
Thank you