hola

this prices are from Portugal so i dont know if in argentina the prices are the same

INTEL CORE 2 QUAD Q6600 G0 (2.40GHZ) SKT 775 BOX --> 154,90 euros
SAPPHIRE HD4850 512MB DDR3 PCI-E --< 166,40 euros
ASUS P5Q PRO --< 112,20 euros
TEAM ELITE KIT 4GB DDR2 800 --< 69,40 euros
CORSAIR TX-650W --< 75,30 euros
SEAGATE 500GB SATA II 32MB --> 67,90 euros
NOX COOLBAY BLACK (JANELA) --> 54,80 euros

Total : 700,90 euros

with that pc you can do everithing ! create music or play the last games (you can remove that grafic card if you dont play games and add a cheap one)

with 700 euros you have a top pc... you just need to buy a monitor