OK, I have managed to Get the Rockstar Game Social Club Application to Launch but the Game still won't.
1. Go into Control Panel> Programmes and Features > Turn Windows Features on and Off, and Scroll down to Microsoft .Net Framework 3.5.* and expand its options and make sure that Both W.C.F HTTP Activation and NON-HTTP Activation are checked. Make the changes if any and Click ok.
2.Go to the Rockstar games social club installation Directory and go into the 1_1_3_0 Folder.
3. In there change the Windows Compatible mode of RGSC.exe to Windows 98-ME OR Windows 95. Both worked fine for me.
4. Try and Launch.
UPDATE:
To get the game to launch:
Go into the GTA Directory and change the Compatiblity mode for LaunchGTAIV.exe to Vista SP2 and Change the Comp' mode of GTAIV.exe to Vista SP1. From then on launch the game from LaunchGTAIV.exe