So if you try to launch EFLC and basically nothing happens (Social club doesn't even open), and/or in event viewer you see a 0xc0000005 error after, then this may help. (I have GTA on steam btw and have had trouble searching for a solution)
I have somehow managed to solve the problem in a list of things I carried out yesterday. So that it may be able to help anyone in the future with the same problem I will explain the path to the solution.
1. I looked into a registry cleaner, downloaded RegGenie and managed to get a free serial key on a youtube vid (http://www.youtube.com/watch?v=Pbp1qJEMBMw
), it showed about 700 errors in my registry and other parts of Windows which it then fixed.
I tried EFLC again but it had not fixed the 0xc0000005 error that I was getting despite the promise of being able to fix it.
2. I then found on the GTA forum that IE9 may cause problems with RGSC ( http://www.gtaforums.com/index.php?showtopic=459257
) so I tried to delete the wininet.dll for IE9 but could not due to permissions so I then uninstalled IE9.
3. Reading the post by dental about putting IE8 wininet.dll in the games folder also helps so I did, taking the one from C:\Windows\winsxs\amd64_microsoft-windows-i..tocolimplementation_31bf3856ad364e35_8.0.7600.20862_none_79346fb94b962189 (closest version I had to what dental used) and put it in EFLCs folder.
I had to restart after this but the game still didn't work.
I tried to play BF3 later but that gave me the 0xc0000005 error too when I have had no issues before so;
4. I did a system restore but my anti-virus was stopping it. After trying by disabling Bitdefender AV and then system restore which didn't work I then uninstalled Bitdefender and the restore worked OK, restored to the 18th which was the last one before RegGenie.
BF3 then worked fine again but didn't try EFLC until this morning and it just worked, RGSC came up asking for the security key (which is where I guess it was crashing before) and now the game is fine.
So whether it was RegGenie sorting the registry or something else im not sure. Remove wininet.dll from EFLC folder doesn't seem to effect the game so I don't know.
I hope this may help others in the future, cheers.