<p>First thing I would try is Vuescan. Assuming that everything works as planned you can then decide to get a second older computer if you'd like. Some people do this as compatibility with older hardware as you're suggesting, and others do it so they don't need to tie up their main computer with scanning.</p>
<p>If Vuescan doesn't work, don't by the software until you figure out why. Buying the software will not make it work or make it work better. The trial is perpetual, you don't just have 30 days. It will however leave a watermark on your images until you buy it. According to Vuescan's page on that scanner you won't need to install any special drivers to get it to work with a Mac http://www.hamrick.com/vuescan/polaroid_sprintscan_120.html<br /> so if the software doesn't work then there's a problem, and buying the software won't solve it.</p>