[CentOS] Yum showing error

Hi I am using centos 5. yum saying following error.. [EMAIL PROTECTED] Desktop]# yum grouplist Loading installonlyn plugin Setting up Group Process Setting up repositories Could not retrieve mirrorlist http://mirrorlist.centos.org/?release=5arch=i386repo=os error was [Errno 14] HTTP Error

[CentOS] there is no priorities.conf file

Hi I am new to Linux. I need to use YUM to install Software. But i can't use YUM. when I give #yum install yum-priorities// following error was i encountering Loading installonlyn plugin Setting up Install Process Setting up repositories Could not retrieve mirrorlist