Thanks for the tip, but I already fixed it.
Booting from the first Fedora cd and choosing to update didn´t help anything (no packages were being installed and the install just finished).
This is how I did it:
I booted using the first Fedora cd using ´linux rescue´. ´chroot /mnt/sysimage´ didn´t work (probably because of missing glibc?), but I used this command to install the glibc rpm I downloaded (using elinks):
rpm -Uvh --root=/mnt/sysimage/ --force glibc-2.3.3-74.i686.rpm
And it installed! It gave a couple of errors, but now at least my kernel would boot again. When I logged in again, I installed glibc another time (but now with a normal /) using
rpm -Uvh --force glibc-2.3.3-74.i686.rpm
This time I got no errors and I was back in business!