[CentOS] Desktop: After yum update and power off, cannot boot new Kernel

Yesterday, in the afternoon, I did "yum update" on my Desktop. Everything seemed AOK. After power down last night, when I powered on this morning, it began to boot the new Kernel and then seemed to die. Instead of getting the progress of the boot on the CRT, the screen was blank and nothing happening. I am now running off the previous Kernel on this box. Is there a fix for this, so I can use the new Kernel? This morning, I did "yum upgrade" on my daughter's box and that is finishing now. If I have the same problem on that box, I will follow on in this thread. TIA, Lanny