eth 0 fails to load at boot up
 

I have a dell server with linux red hat 7.0 preinstalled. one day by accident i lost stepped on the power strip and The server rebooted , after that day The ethernet card fails to load , and i need to manually enter the ifup command to bring it up again. however other services fail to load, like dns,etc... although the appear to be working. I can i make sure that the etho card will load next time the server loads , i check the ifcfg-etho file and its indeed has under the onboot = yes. what can be happening?