Do the following steps as:

rpm -ivh ftp://server1.example.com/pub/kernel-hugemem-*

2. vi /etc/grub.conf

Set the default to new kernel

default=0

Example of /etc/grub.conf

default=0

timeout=5

splashimage=(hd0,0)/grub/splash.xpm.gz

hiddenmenu

title Red Hat Enterprise Linux ES (2.6.9-5.ELhugemem)

root (hd0,0)

kernel /vmlinuz-2.6.9-5.ELhugemem ro root=LABEL=/1 rhgb quiet

initrd /initrd-2.6.9-5.ELhugemem.img

title Red Hat Enterprise Linux ES (2.6.9-5.EL)

root (hd0,0)

kernel /vmlinuz-2.6.9-5.EL ro root=LABEL=/1 rhgb quiet

initrd /initrd-2.6.9-5.EL.img

rpm command is used to install, update and remove the rpm package. -ivh option is install, verbose, and display the hash mark.