Reinstalling Windows is just a tad too drastic, this is not a Windows issue. This is a SODE and an add-on issue - 2 issues. You should contact FSLabs for the add-on issue, you already know how to fix the SODE issue.
For reinstalling P3D: after this post, I am going to paste in a document that shows you how to completely remove a P3D installation, including all traces of it. It looks more daunting than it really is....
Jorgen
This is how I perform a clean install on Prepar3D v. 5, if you have v. 4 just say "v4" where the instructions say "v5".
READ EVERYTHING BEFORE YOU PROCEED.
WARNING: A clean install will mean just that - beware that all add-ons will not reappear in P3D, you will need to re-add or reinstall them, and that is beyond the scope of this tutorial.
If you're doing a clean uninstall-reinstall because your installation was damaged in some drastic way, for instance a disk crash, some parts of this process will seem superfluous. Just follow the steps that are relevant - it will be obvious which are. But, if your installation was damaged to the extent that you cannot uninstall completely, then you may have a license issue. To resolve that, email the licensing department at
licensing@prepar3d.com.
When you have downloaded your new sim, do not bother with checking checksums, unless you have a suspicion that something went wrong during the download. Modern-day browsers, no matter which one, will tell you if that happens, and the utility you use for unpacking will also tell you.
I have my P3D v. 5 on my H: drive, a dedicated SSD. It is in a folder called P3D V5. For your installation substitute your own installation location, but - IMPORTANT - do NOT install to the default location of C:\Program Files. If you had P3D installed there, then install to somewhere else when you reinstall, for instance to C:\P3D.
The whole process begins with going to the Control Panel and uninstalling the old version: first uninstall the SDK, then Scenery, Content, Client and Professional Plus (or Academic) in that order.
Remove whatever remains under the folder P3D V5.
If you have moved your Documents folder, go to its new location and remove it from there.
Go to the root of C: drive, in the Search box in the top right-hand corner type "Prepar3D v5" (without the quotation marks) in Windows Explorer (that is File Explorer, not Internet Explorer). Delete everything that is found. Some items cannot be deleted, go Skip on those items.
Empty your Temp folders (not really necessary, but they should be emptied once in a while).
Empty your Recycle Bin.
Clean Registry, using Eusing's Free Registry Cleaner. (This is the one I use, there are plenty of others).
Reboot.
Right-click on P3D's Setup_Prepar3D.exe and select Run as Administrator, and on the first screen, under Options, select to install in the P3D V5 folder on the H: drive. This is for my own use, see above for installing on another drive.
When the installation is finished. go into the P3D v5 folder, create a folder named SDK, install SDK to there.
Right-click on the Prepar3D icon on the desktop, select Properties. Go to the Compatibility tab, put a check mark in the box "Run this program as Administrator". Click Apply, then OK.
Start P3D, fly the default flight out of KRND (KVPS if v. 4) for a couple of minutes. Shut down P3D, reboot.
Go into the SDK subfolder, right-click on ConfigureSDK.exe and select Run as Administrator. Answer Yes to the question that comes up.
Now you are ready to explore the world of Prepar3D.
If you reinstalled P3D because you experienced problems with add-ons, then test the flights where you experienced problems BEFORE you install ANY add-ons. Install your add-ons ONE AT A TIME, testing between each.