Been running linux for 4 years now and gentoo for the last year with only occasional hurdles. One day about 3 weeks ago I upgraded to the lastest stable versions of X, xterm and firefox. Everything appeared to be working fine when I finished, so I shutdown the computer. When I tried to boot up the next day (and ever since), all I get is
LILO: Loading Gentoo.....
and then it hangs. Indefinately. I can access the BIOS so I was able to change the boot sequence and boot from a GPartEd (partition editor) cd that I have. From here I can manually mount the filesystem and poke around in my files, but the problem is I dont know what I'm looking for. I checked /var/log/messages, but the last recorded message is from shutdown the day I did my upgrades, and all appears to be normal. Now it doesn't boot up far enough to write anything to this file, or to dmesg.
I know this isn't a lot of info to go on, and I'm not really looking for a solution, just somewhere to start. Is there another way to find error messages?? I'd like to leave reformatting as a last resort...

thanks in advance... 3 wks without a computer is a long time!

Boot the gentoo live cd.
chroot back into your system
unemerge lilo and then re-emerge lilo (or grub)
re-run lilo (or grub) to save the changes
exit and reboot.

Finally, got my hands on the livecd. Forgive me if I'm missing something really obvious, but the login screen will not recognize my root OR user passwords. (I also tried logging in as "root" with no password, ie just pressing "enter" at the password prompt.) After a time delay it logs in as default user "gentoo". This gets me an empty blue screen where, no matter what mouse or keyboard key I use, nothing happens. Am I doing something wrong?

Usually the gentoo live cds are good a picking up hardware. Its a little shocking that this one doesn't detect the keyboard/mouse. There is always the Knoppix Live CD that you could try. Maybe that one will give you better luck.
You did bring up a good point though. When you chroot into the current gentoo install to emerge lilo, you'll also have to do a passwd on root again.

It does actually detect the mouse, and I can move the cursor around, but clicking the buttons doesn't do anything. I believe that some combination of Alt-Ctrl-F1 is what I need to launch a terminal (right?), but this also results in.... nothing. Maybe its a problem with the CD, I had to have a (windows) friend burn it for me so who knows. I'll see about trying Knoppix

Really appreciate the help