I can install GTA IV on pc but when I click on it to play it nothing pops up or it don't even start.... nothing happens, I don't know if the game is blocked or anything.
has anyone got any ideas on why its not starting???
Is it downloaded from steam or do you have the disc?
Being an oldish game i think you will have to download the latest version of social club from Rockstar support.
http://support.rockstargames.com/entries/21917823-Manual-Link-to-Social-Club-Application-Download
I had to do this with Max Payne 3 which is even newer than GTA IV.
You cannot uninstall social club, so just install it over the top of the old version.