yum is stuck

Suddenly yum refused to run (using Fedora 8 here). Apparently there can be many reasons for this. You can get yum to give you some more info by running it like this:
yum -d 10
The last two lines I then get from yum are:
Reading Local RPMDBM
Setting up Package Sacks

The steps I took to fix it (one or more may work for you):

• rebuild the RPM database:
  rm /var/lib/rpm/__db*
  rpm --rebuilddb
  (takes a while to run)
• rm /var/run/yum.pid
• yum clean all
• to (temporarily) disable extra repositories, I created a subdirectory disabled in the repositories directory:
  cd /etc/yum.repos.d
  mkdir disabled
  mv freshrpms.repo disabled
  mv livna.repo disabled
  

This did the trick, unfortunately I didn't test properly, so now I don't know which of the steps were required and which weren't...