I've just done a fresh install of P3D v4.5 on my recently re-built PC.
So far, I've installed P3D and played around a little to check the frame-rate, etc. Then, I downloaded the latest version of the Airbus A318/A319 package and installed it. I disabled all antivirus as usual, and rebooted after what appeared to be a perfect install. However, now when I launch P3D, I get the loading screen for a few seconds, and then nothing. No Scenario Screen to select aircraft, airport, etc. Although in Task Manager, I can see P3D is running and taking a small percentage of the processor, and it's attached to the correct GPU so it SHOULD be on screen.
Looking at the P3D forum, I tried their suggestion of using the "delete generated files" link, which clears the add-ons.cfg. P3D started working again. I removed and re-installed the A318 and exactly the same problem happened - you get the loading screen, then it disappears and nothing except an entry in Task Manager to say P3D is running.
System is running Windows 10 Professional, version 1809 (build 17763.615) with an i7-4790K processor and 16GB RAM.
I checked the contents of the add-ons.cfg file, which contains just the following entry
PATH=C:\Program Files (x86)\aerosoft\Aerosoft A318-A319 Professional
TITLE=Aerosoft A318-A319 Professional
The logfile from the Aerosoft Updater shows:
Product Name: Aerosoft A318-A319 Professional for Prepar3D v4.x
Add-on Path: C:\Program Files (x86)\aerosoft\Aerosoft A318-A319 Professional
Installed version: 126.96.36.199
No updates available for this product!
Absolutely ANY help would be welcome - I miss having the Airbus available to fly!