after BIOS splash, will not boot, asked to select OS, can't

[ablech]

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 version1.99-21ubuntu3.4

Then 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 mode

Previous Linux versions

Memory 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 screen

Can anyone help me please?

Intel Core i5-2500
ASUS P8Z68-V LX Intel Motherboard
G. Skill Ripjaws series F3-12800CL9D-8GBRL (4GB x2)
Plextor 128GB M5S Series SSD



Update:
If I press 'e' it reads as follows:

setparams 'Linux Mint 13 MATE 64-bit, 3.2.0-31-generic (/dev/sdb2)'

recordfail

gfxmode $linnux_gfx_mode

insmod part_gpt

insmod ext2

set 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

[srs5694]

What you're seeing is a GRUB 2 menu. Many configurations hide this unless you press a key during boot, but such a menu can be the default in other configurations. The GRUB 2 menu in and of itself isn't a sign of a serious problem (although you could reconfigure the system to bypass the menu in various ways, if you like). I'll therefore restrict my comments for now to the real problem -- your inability to boot when you select the Linux options....

It's unclear from the information you've presented precisely what's causing the problem. My guess is that a kernel upgrade went bad -- maybe a file is corrupt on the hard disk or the upgrade script wrote the wrong data into the GRUB configuration file. To learn more, please boot with an emergency system and run the Boot Info Script. This will create a file called RESULTS.txt. Post that file here, either in code tags or as an attachment. It may provide a clue about what's going wrong.

[ablech]

How do I boot to an emergency system? I take it you don't mean the "recovery mode" -- when I try that, it restarts as I stated. I'm not sure how to boot to an emergency system

[srs5694]

Try System Rescue CD or Parted Magic. There are numerous others.