GRUB HV Frequency Over range

This is happening because the GRUB2 boot loader is using a video mode that is not supported by your screen and/or video card. The problem can usually be fixed by specifying a low resolution in GRUB2's configuration.

First, I recommend backing up the configuration file, in case you make a mistake while editing it. To back it up, open a Terminal window (Ctrl+Alt+T) and run the following command by pasting it into the Terminal and pressing enter:

sudo cp /etc/default/grub /etc/default/grub.old

You may be prompted for your password. If so, you won't see any placeholder characters (like *) as you type it in, but that is not a problem. Just type it in and press enter.

Then open the file in a text editor by running this command:

gksu gedit /etc/default/grub

In the text editor window that comes up, find the line that says:

#GRUB_GFXMODE=640x480

Remove the leading # character, so the line now says:

GRUB_GFXMODE=640x480

Then save the file and quit the text editor.

Now you have to apply the new configuration. To do that, run this command:

sudo update-grub

Then shut down and restart your computer, and see if the problem is fixed. If it is (it probably will be), you can mark this question as Solved. If it is not, please post a reply here describing what, if anything, changed.