I was thinking of reinstalling GTA IV and LCPDFR but had a question. I seem to remember what a pain it was to get working, if I remove the added scripts from the script folder and reinstall the game will it over right the changed files such as the added cars and put all the factory cars back in or do I need a clean install for that? 

If you reinstall, GTA IV will overwrite all files but it will not remove any files. 

If you reinstall, GTA IV will overwrite all files but it will not remove any files. 

 

I believe that is only if you repair the installation. By uninstalling, you are removing the whole game. If it does leave some files behind, deleting the GTA IV folder (if there still is one) after the uninstall should fix that. Then, you may proceed with installing the game as you did when you first installed it.

I am a bit worried about the keys, I have the one for the game from amazon but GFWL required a different key. it really was a pain to get everything communicating and working. Now I try to log into GFWL and just get a server error. It logs me in game fine but not in the GFWS stand alone program. I have no clue what they key for that was. 

I have never bought any games from Amazon, so I have no clue either.