Originally posted by Ira G4 non-Intel at home, so I'm screwed. Not supported.
And only the original CS to boot.
No problem bringing the files in as layers, but that registration is a biggie.
My office computer will support it, I'm sure. But who the hell cares about the OFFICE!?
In Photoshop, an old trick I use to register elements from time to time in my day job (graphic design) is to chromatically invert (ctrl+i on pc, cmd+i on mac) the layer you're trying to register, which should be on top of the target layer you're trying to register it to. Then set the opacity of the inverted layer to 50%.
Try this first with 2 identical source layers, top one inverted to negative; the colours in the 2 layers cancel each other out, and you'll see a perfect, 50% grey image. Move the top layer a few pixels to the left and right, and you'll quickly see how easy it is to register the images in this setup.
With 2 marginally different layers, such as 2 tripod photos shot at different exposures, you won't end up with the perfectly gray composite that i described, but it'll still be far easier to register the images than by looking at the layer you're attempting to register as a transparent positive... viewing the composite with the 50% transparent negative really helps identify clear pixel-perfect alignment.
Hope this helps!