I had the same problem using Fedora Core 3 and this is what I did to fix it. I'll assume that it'll work for the other Fedora Core's (but I won't garuntee it). First of all, make sure you are the root user. Then use yum[1] to remove mysql-server:
# su
Password:
# yum remove mysql-server
After yum removes mysql-server, you have to go in and manually remove any other conflicting mysql elements:
# rm -rf /var/lib/mysql (Make sure that you don't have any important database files in here. If you do, move them.)
# rm /etc/my.cnf (These two items will be re-installed in the next step.)
The next thing you want to do is re-install mysql-server:
# yum install mysql-server
The last thing to do is start the mysql daemon:
# /etc/init.d/mysqld start
That's it. I hope it works for all of you!!!
[1] The yum.conf file that comes with Fedora is very slow. If you want one that uses faster repositories you can pick it up here:
http://www.phys.psu.edu/~maskey
After you get to the site, right-click the yum.conf file and save link target as. Make sure you change the ownership and group of the file to root (if it isn't already) and replace (or rename) your old yum.conf located in /etc.
# su
Password:
# cd ~/ (Where ~ is the path to the directory that you placed the downloaded yum.conf file.)
# chown root:root yum.conf
# mv /etc/yum.conf /etc/yum.conf.old (This is the yum.conf that comes w/ Fedora.)
# cp ~/yum.conf /etc/ (Where ~ is the path to the directory that you placed the downloaded yum.conf file.)
This should make installing packages much faster.