There are lots of things to try before throwing in the towel. I'll start by shutting everything off in the BIOS. Things like COM, LPT, USB2, etc. should be disabled. Also disable ACPI for the preliminary setup as well as anything else you consider unnecessary or optional. Also remove all add on cards for the initial tests.
The goal is to get a complete boot to the login prompt. Once there you can start adding things to the setup until you are where you need to be.
Such problems are usually due to IRQ issues, RAM as Dismember pointed out or, in some isolated cases, ACPI.
When I run into a stubborn setup, that's what I do. Strip it down to the bone, get a prompt and then start adding options and hardware until I get to where I need to go. Works every time.
