Need help with updating processor and cpus

APPROXIMATE PURCHASE DATE: Mid Oct-late Oct

SYSTEM USAGE FROM MOST TO LEAST IMPORTANT: gaming, surfing the internet, watching movies/itunes)

PARTS NOT REQUIRED: Keyboard, Hard Drive, CD Rom, Power supply (depends on needs), mouse, keyboard, monitor.

PREFERRED WEBSITE(S) FOR PARTS: Newegg.com, or any cheap but reliable US site.

PARTS PREFERENCES: Mid-Tower case (any brand), Intel, AMD (Depends!!)

OVERCLOCKING: Yes SLI OR CROSSFIRE: Yes

MONITOR RESOLUTION: 1280x1024

ADDITIONAL COMMENTS: Would like to have a non-lagging computer. Less overheating. Great for playing while recording the games.


Also would consider buying new Ram too.






Okay here are my Computer Specs

OS
Window Xp 2002

Processor
Intel Celeron 2.7GHz
Socket 478 mPGA

Motherboard
MS-6577 (Giovani, Giovani2)

Power Supply
500w

Memory
1 GB
(512mb x 2)

Hard Drive
Western Digital 500GB

Video Card
PNY 8400GS 512mb PCI
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I play mostly Combat Arms.
(Here is link to Specs for game)
http://combatarms.nexon.net/Download/ClientPatches.aspx

Case: Good for airflow, many fan openings, color/looks don't matter as long as it has a good airflow (Case to be no more than $50, also could be from other websites)

Crossfire: Doesn't matter

Playing Settings: Medium

Price Range: $350-$450

Website to buy parts: Newegg.com



Thank you. I would love to hear your suggestions.