Well, if I had to guess, I would say that your kernel has become corrupted. I think you're in for a world of hurt here. I think you're better off just doing a fresh install of Linux. Sorry but I don't know anything about compliling kernels. I leave that to the experts.
Can you boot XP okay or is that screwed up as well?? If so, then I would just start over and select LILO this time. Some don't like it, but I think i'ts better because LILo resides in your MBR.