If you can afford to buy an additional hard disk (same size or larger than existing) rather than a new PC, then you have the option of cloning the existing disk to the new, then putting the new one in the PC / laptop and doing an upgrade, safe in the knowledge that if it turns out to be a mistake you can revert to your existing disk by simply putting it back. Alternatively, with your existing disk safely tucked away, you can also try a clean install on the new disk, and keep the existing as a backup - put it in an external USB caddy to make it really easy to transfer data (an external caddy also simplifies cloning).
SD