500 years is too long for modern tech. You will definitely need many copies of different types of storage, down to atomic-level records such as DNA. GitHub's Arctic Code or Amazon vault looks like the first Godzilla computers, but you're asking for a "500-years PC".
Perhaps there will be a technology that allows you to write site files in the DNA directly of your children and run a micro-DNA web server in the body, and your grandchildren can surf on your Internet data in the brain.
This DNA writing idea is premised on the concept that most of our DNA is "junk", which is an increasingly unlikely idea. Most of it does not code for proteins, that's true. We are slowly uncovering more and more functions for the rest.
Who said anything about modifying our existing genome? Perhaps in the future we’ll be able to add extra biologically inert genetic material solely for the purpose of permanently storing information, passed from generation to generation.
It doesn't need to be human DNA, indeed the part chosen may not 'make' it 500 years. While I have no desire to do this, choosing a variety of other life seems more viable, and more easily rediscovered if necessary.
