i want gaming pc but i dont know much about Pc parts:
these on the specs of the Pc im looking to buy

INTEL CORE 2 QUAD Q6600 9.6 GHZ 8MB CACHE 1066 MHZ
4096 MB DDR2 667 BRANDED MEMORY
500 GB 16MB CACHE SATA HARD DRIVE
20X DUAL LAYER LIGHTSCRIBE DVDRW DRIVE
GIGABIT LAN 1000 MB/S NETWORK CARD
ONBOARD SOUND
ASROCK 4 CORE GLAN MOTHERBOARD
ATI HD 2400 1GB HYPER MEMORY DIRECT X10 PCI EXPRESS GRAPHICS CARD
4X USB2 PORTS IN THE BACK
2X USB2 PORTS IN THE FRONT

this all for under £400

is it worth it?
if not, could help me build a gaming rig please, like the best parts.
my location is the UK, i can buy online aswell. My budget hmmm around £500.
i dont need any mouse, monitor of keboard .

thanks