I have determined using Hiren's Boot CD that my hard drive is in fact failing. It started by failing to boot into Windows or Linux partitions on my computer, and then I downloaded Hiren's, burned to a live USB and ran a few tests, indicating my hard drive was failing.
So my question isn't about recovering the data (already done) or replacing the hard drive, but rather is it viable to use a live CD indefinitely on my PC or will the screwed up hard drive have any negative impacts on anything?