fsxstart up after install problem

[virtuali]

The only thing I could not do is delete the simconnect files as whatever I did the permission was denied.

You will have to boot Windows into Safe Mode in order to do that. And THEN, make an FSX repair AND an FSX SP2 repair too.

I uninstalled and reinstalled FSX SP2.

You should have done a repair, instead. And, as I've said, an FSX repair too.

Is completely uninstalling and reinstalling FSX likely to make difference?

It depends if the FSX installer can fix the problem you are having with your Windows installation. Sometimes is able to fix corrupted/missing libraries, but sometimes only a Windows reinstall can fix it.

The user in this thread had the same problem:

http://www.fsdreamteam.com/forum/index.php/topic,9785.msg77313.html#msg77313

And it was solved by reinstalling Windows.

[skytrain2]

I did everything you recommended and except reintall windows from scratch but I did an update of Windaows 7 from the CD. Still no joy. Then I thought, the problem started after uninsatlling P3D. I reinstalled P3D and then GSX into FSX and not into P3D following all the recommendations from you. It initally gave the same error message. I decided to run it anyway and FSX did not crash. Restarting FSX became normal and GSX is working. Thank you for your guidance without which I would never have resolvd the issue. I do not use P3D but I will leave it in just for GSX. At present it is working only on your airports and the authintication is refusing even thought I have the FSDTGSX-XXXX-XXXX-XXXX-XXX-XXX Number.
I am sure this will be an easier problem to resolve. This is the same computer on which it worked with P3D before

[virtuali]

the authentication is refusing even thought I have the FSDTGSX-XXXX-XXXX-XXXX-XXX-XXX Number.

Please, clarify this problem. What do you mean with "refusing" ? Do you have some error message ? If yes, which one ?

[skytrain2]

Since my last post, I reinstlled over the previous one and when I authenticated it worked. One again thank you for yuour support and patience. I reiterate that I made such a fuss because GSX is the best addon for FSX by far and I was miserble when it did not work. Thanks for such a wonderful project. My problem is fully resolved.