Stuck on "Enter runlevel"

I am a bit of a linux newbie, so if you need more information, let me know.

On boot, my machine (running Linux 7.3) goes through a bunch of hda: dma_intr and hda: read_intr (after it disables dma) errors. It then gives the message: end_request: I/O error, dev 03:06 (hda), sector 7606336. It gave this and a similar errors earlier in its run of errors. Then it dumps me onto Enter runlevel, and no matter what I enter it says "No processes left at this runlevel" and then freezes. If anyone has any idea or needs more info, please let me know ASAP.

What numbers have you tried? 3 should work, dumping you at a login prompt.