Having had to reformat my C drive, re-installed FS9 a couple of times to get it working, re-installed PMDG once and so on, I seem to have got in a right old mess.I am now trying to re-install PMDG 747 into FS9 which is now stable. But I keep getting an error message telling me I have a later version of PMDG747 already installed. I now cannot seem to uninstall the previous version and cannot start again.What a mess!Any help would be appreciated. These are all licensed programs I am using.ThanksRob Payne;(

Rob,Things are not looking to good if you have had to re-install FS9 a few times to get it working. You need a stable FS9. This may not be the best option, but it is what I would do:1. Un-install any addon programs that you have, then un-install FS9,2. then delete the main FS9 folder in c:Program FilesMicrosoft GamesFS9 - if you un-install FS9 and not other add on programs (ie PMDG) then this folder will still be left on the hard drive3. Reboot pc4. Use a registry cleaner to clean out your registry.5. Load FS9 back on the pc6. Only load addons when you have FS9 stable, and do so in this order, 737/747/747F (that is if you have both the 737 and the 747)Hope this helps.Justin

JustinThanks for taking the time to reply.Tried all of that now and it will still not load. There must be some entry hidden away in the Registry or some file somewhere on my C drive. Rob}(

thanks for the replies.Had a very prompt reply from Paul Gollnick of PMDG which has resolved the issue.:) Rob

>Use the pmdg 737 tng removal tool. Here is the link.That has nothing to do with the 744 install...