I'm not sure what do you mean with "Uninstall button greyed out".
Maybe you confused it with the "De-Activate" button ? It's just normal that button is disabled, since what it does, is to remove the Activation of a purchased product, so you can reclaim it to install in a new hardware, without consuming a new one. Of course, it's disabled if the product is still in Trial mode.
Also, you don't say if you INSTALLED XPOI or not. If you installed it, you Uninstall it like every other Windows software in the world, from the "Add/Remove Programs" section of the Addon Manager.
If you haven't installed it, there's nothing to uninstall to begin with...
if you haven't activated something, the Addon Manager will list something in its list to be "In Trial mode", regardless if it's installed or not. As explained many times on the forum, the activation status is entirely unrelated to the installation, because the activation stays in your Windows registry, and it won't change it by uninstalling the product or even the whole sim.
This means, regardless if you have installed XPOI or not, if you haven't activated it (which, again, can be done independently from its installation) it will always display as "In Trial mode" and, since XPOI is NOT a scenery, the Addon Manager will just show "Active" or "In Trial", without its *Installation* status, which really means "Installed in the Scenery Library", that is relevant for sceneries only.
