Gaming PC Help!

I want to buld a gaming PC that will run ARMA 2 on Medium Settings for around 500 hundred dollars for everything including the OS!! Here are the Specs:             (Parts on Newegg.com)

 

Case - NZXT LEXA S LEXS - 001BK Black Steel ATX Mid Tower Computer Case - $80

MotherBoard - ASRock 970 EXTREME3 AM3+ AMD 970 SATA 6Gb/s USB 3.0 ATX AMD Motherboard - $85

GPU - SAPPHIRE Vapor-X 100358VXL Radeon HD 7770 GHz Edition 1GB 128-bit - $140

CPU - AMD Phenom II X4 965 Black Edition - $85

RAM - G.SKILL Ripjaws X Series 8GB (2 x 4GB) 240-Pin DDR3 SDRAM DDR3 1600 - $40

Power Supply - CORSAIR TX Series CMPSU-750TX 750W - $130

HDD - Seagate Barracuda ST1000DM003 1TB 7200 RPM 64MB Cache - $70

DVD Drive - ASUS DRW-24B1ST/BLK/B/AS Black SATA 24X DVD Burner - Bulk - OEM - $20

OS - Windows 7 - $100

 

                                                                                                                               Tota on Neweggl: $750

 

I know this will probalby not happen but i really want to keep it under 500 dollars. 

Also this is my first build so i am going to start out low

Please help because the main reason i want to get into PC Gaming is to play DayZ and if one you guys has a 500 dollar PC and can run DAYZ on medium settings, please help!!

Hello To start with use this:

http://pcpartpicker.com/

Get your build built on this site and it will give you the best deals it can find for you.

I'd say, drop the 7770 and get the 6850 1GB or 7850 2GB. 650w psu is enough for your rig, but it's your choice.