I'm running Linux Mint 13 MATE 64-bit. Everything has been working for several weeks. Yesterday, when I tried to boot up my computer, after the BIOS screen flashes I reach a screen with a black background that reads at the top:GNU GRUB version1.99-21ubuntu3.4Then there is a box in which I can select from the following lines:Linux Mint 13 MATE 64-bit, 3.2.0-31-generic (/dev/sdb2)Linux Mint 13 MATE 64-bit, 3.2.0-31-generic (/dev/sdb2) -- recovery modePrevious Linux versionsMemory test (memtest86+)Memory test (memtest86+, serial console 115200)At the bottom it reads:Use the  and  keys to select which entry is highlighed. Press enter to boot the selected OS, 'e' to edit the commands before booting or 'c' for a command-line.I have no idea why it started doing this and, worse, I have no idea how to get out of here. No matter which option I select, I can't get it to boot the OS. If I select either of the first two, it reboots to splash the BIOS and then I'm right back where I started. If I choose Previous Linux versions I get essentially the same screen with only two choices (which are the same as the first two choices listed above, Linux 13 MATE and the recovery mode). Again, choosing either one of those results in a reboot. If I try to run either of the memtest options, it reads:error: unknown command 'linux16',Press any key to continue...Then it brings me back to the same screenCan anyone help me please?Hardware Specification:Intel Core i5-2500; ASUS P8Z68-V LX Intel Motherboard; G. Skill Ripjaws series F3-12800CL9D-8GBRL (4GB x2);Plextor 128GB M5S Series SSDupdate:If I press 'e' it reads as follows:setparams 'Linux Mint 13 MATE 64-bit, 3.2.0-31-generic (/dev/sdb2)'recordfailgfxmode $linnux_gfx_modeinsmod part_gptinsmod ext2set root = '(hd1,gpt2)'search --no-floppy --fs-uuid --set=root 249aaa9-029d-4599-b25d-92003c49e087    linux /boot/vmlinuz-3.2.0-31-generic root=UUID=2492aaa9-029d-4599-b25d-92003c49e087 ro \quiet splash $vt_handoff initrd /boot/initrd.img-3.2.0-31-generic
after BIOS splash, will not boot, asked to select OS, but can't
boot;grub