I've been a happy user of Linux Mint Debian Edition for about six months now.
Today, while trying to get some games working, I decided to install the official AMD Radeon HD 6xxx series driver, from the AMD website. The driver installation went smoothly, but afterwards all applications requiring OpenGL stopped working, complaining about a missing libgl.so.1 file.
I tried restarting Linux Mint, but it wouldn't boot correctly, simply launching into a black screen. I assume that there is some issue in the AMD driver that I installed that breaks graphics completely.
I tried booting from my Linux Mint Debian install CD, but it wouldn't boot - there's only a blank prompt when I try to use it.
Finally, I saw the instructions on viewtopic.php?f=46&t=122257 and tried following them. It did not fix the issue, and furthermore GRUB stopped working immediately afterward (I'm not sure if it's connected to these instructions or not, but it's a weird coincidence). Now I can't do anything - when I turn on my computer, there's just a blank prompt instead of GRUB, I can't dual-boot into Windows, and I still can't use my install CD.
What can I do?