I'm running a P4 1.8 ghz with 512mb of ram and I have a 40 gig internal HD and an 80 gig external. I have Vista on the 40 gig. Is there anyway to install WHS in a separate partition on the same HD?
No. WHS formats the entire drive and sets it up for its own purposes. WHS is not and won't be meant for use in a dual boot environment. This requires a dedicated machine for proper testing as that is how the product will be shipped.