wow!! this forum gives me no help at all.
I thinking... only because this:
Buy the full version or uninstall.
might have been written in haste.
For the trial in which 60 days from any previous install of a trial has passed:
The answer is uninstall and then either buy it or live without it.
Reason being... if you buy it, you still need to uninstall the trial (and reboot) in order to install the paid (with a reboot) and have it work properly.
FYI the trial is a 60 day trial and subsequent reinstalls or installs of newer trials won't work past the original 60.
For a paid version: if following the prompts during install don't work, contact support and give them your email/registration info.