Red Hat Kernel Upgrade problem

I'm using a Red Hat 4 Enterprise Linux. But, when I upgrade the kernel, an error occurred. And after, when computer is booting with new kernel (red hat enterprıse 2.6.9-100.el), I receive the following the error. mkrootdev: label /1 not found mount: error 2 mountıng ext 3 mount: error 2 mountıng none switchroot : mount failed :22 umount /initrd/dev failed :2 kernel panic -not syncing :Attemped to kill init! After, when I try to boot the system with old kernel (red hat enterprıse 2.6.9-42.el), the system successfully booted. My question is; when I rebooted the system, it attempt to boot with new kernel every time and so I have got to choose the old kernel with hand all the time. How to get rid from this problem?How can I uninstall the new kernel without problem? or How can I use the new kernel without problem? something like this grub.conf; "default=0 timeout=5 splashimage=(hd0,0)/boot/grub/splash.xpm.gz hiddenmenu title Red Hat Enterprise Linux ES (2.6.9-100.ELsmp) root (hd0,0) kernel /boot/vmlinuz-2.6.9-100.ELsmp ro root=LABEL=/1 rhgb quiet initrd /boot/initrd-2.6.9-100.ELsmp.img title Red Hat Enterprise Linux ES (2.6.9-100.EL) root (hd0,0) kernel /boot/vmlinuz-2.6.9-100.EL ro root=LABEL=/1 rhgb quiet initrd /boot/initrd-2.6.9-100.EL.img title Red Hat Enterprise Linux ES (2.6.9-42.ELsmp) root (hd0,0)"