What type of computer do you have? Please open a terminal (Applications>Accessories>Terminal) and type 'lspci' and post the output here. Also, please attach the file /var/log/Xorg.0.log. This will help narrow down the cause of your problem.
What type of computer do you have? Please open a terminal (Applications> Accessories> Terminal) and type 'lspci' and post the output here. Also, please attach the file /var/log/ Xorg.0. log. This will help narrow down the cause of your problem.