Installing Redhat Linux 7.0 Update over

I had a problem booting the install CD for Redhat 7.0 Update – Redhat 6.1 was already on the system. The install CD failed to boot and lockedup while running “Anaconda”. I fixed the problem in a round about way. First I installed Storm2000 Linux over the Redhat 6.1. Then I could install Redhat 7.0 cleanly.
Does anyone have any insights ??
thanks, Bobn