You can safely exclude ANY issue with the software running, xml files, antivirus, etc. because, if you are seeing all the menus, it means everything is fine and there are no problems with the software, which is running fine.
Standard POIs and Wikipedia are both dependent on the Internet connection, while Navaids and Airfields are not, since they are read directly from FSX. If Navaids and Airfields is the only thing you are seeing now, it's might be because XPOI can't connect to the internet, for any reason, which can be either a firewall you are running, or simply the geonames.org database which might be momentarily down. However, XPOI should issue a message about not being able to connect to geonames.org.
However, if you can't connect to the internet, the POI search function shouldn't work either.
If the search works, and you just don't see POIs, check your the XPOI menu for their settings: it's possible you haven't turned them on ? Or, more precisely, there are no POIs for the classes which are turned on in the area you are flying ?