Can this computer run GTA 4 ?

Short answer yes, that is quite a bit above the minimum requirements.

Edit
Actually im not sure, you only need an athlon x2 64 2.4 GHZ processor and 2G of RAM to run GTA 4. However im not sure if you graphics hardware will be good enough. I goggled the name of you graphics hardware and apparently its a kind of integrated graphics, which are apparently not so good for gaming. If that's the case then you need a graphics card as opposed to integrated graphics, one which has at least 256MB of memory.

Edit
Don't listen to the others guys, your system is pretty good and more than sufficient with the exception of the graphics which are not so good. You will need a dedicated graphics card to play this game.

Minimum System Requirements

OS: Windows Vista - Service Pack 1 / XP - Service Pack 3
Processor: Intel Core 2 Duo 1.8Ghz, AMD Athlon X2 64 2.4Ghz
Memory: 1.5GB, 16GB Free Hard Drive Space
Video Card: 256MB NVIDIA 7900 / 256MB ATI X1900

You will barely be able to run it low settings. 20 FPS everything lowest AT MOST.

IS that AMD over clocked cos it sucks ***. TBH

no