PCI not using MMCConfig
 

I installed the Red Hat 5 on P4, it is ok. Again I installed the Red Hat 5 on my PC dual core, after installation GUI is not displaying, before the message is :

PIC : not using MMC Config
PCI : Bios bug MCFG area at e000000 is E820 ...

So what did Red Hat support say about this? You're using Red Hat Enterprise five, which is a commercial, PAY FOR, product. When you pay, you get support. This bug is mentioned in their knowledgebase (which, as a paying member, you also have access to). RH5 is a bit old, but still supported...if this is a new installation, you should go for the latest 6.x release. If you're NOT paying, you SHOULD NOT BE USING RHEL, but should load CentOS instead.

And if you tried to look up the messages in Google, you'd see they're informing you of a BIOS bug (and it even says that clearly in the message). Have you looked for an update to your BIOS on the manufacturers website?