yum Command Hangs on Running Transaction Test Message Error and Solution

When I run 'yum install package' or 'yum update' commands the yum command works normally until Running Transaction Test and hangs until the yum process is killed manually using the kill command. How do I fix this problem under CentOS Linux 5.x AMD64 running on HP server?

This error indicates that other duplicate yum processes running on the system or older yum process causing problem. To fix this problem either reboot the server or type the following commands:
# /bin/rm /var/lib/rpm/__db.*
# cd /var/cache/yum
# /bin/rm -rf *
# yum clean all
# yum update
If you still get the same problem just reboot the server.