What you are doing has been done.
You need to make sure you are loading either the smp or the large memory kernel.
If you don't have the kernel, you need to install it. The Update interface will let you do it, or you can download the rpms from RedHat. I don't think a recompile is required.
If you installed it, should see that choice at boot time.
You can edit the grub.conf file to change the default boot kernel as well.
SEP
Steven E Protter
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