720 dollar gaming pc

Try to have a fx 6300. Include a dvd drive, wifi adapter, windows, and a decent monitor (1080p)

http://pcpartpicker.com/p/1Qsjf

Best I could do, and it was difficult. No overclocking on this build.

you can really do more if you get a quad core

http://pcpartpicker.com/p/1QsAV

Here's what I came up with.  I went over a bit.  http://pcpartpicker.com/p/1QsF2

CPU: AMD FX-6300 3.5GHz 6-Core Processor.  As requested by OP

MOBO: ASRock 970 EXTREME4 ATX AM3+ Motherboard.  Had what I need, is a full ATX board, usb 3.0, and and a somewhat recent chipset.

RAM: Kingston Black Series 8GB (2 x 4GB) DDR3-1333 Memory.  Would prefer 1600mhz+, but I couldn't fit it into the budget.

HDD: Western Digital Caviar Blue 1TB 3.5" 7200RPM Internal Hard Drive.  Typical stuff.

GPU: Sapphire Radeon HD 7850 2GB Video Card.  Cheapest 2GB version with a good cooler.  I had a 1GB version and it was great.

WLAN: TP-Link TL-WN751ND 802.11b/g/n PCI Wi-Fi Adapter.  As requested.  I also don't like USB wifi adapters, and TP-Link is pretty good in my experience.

Case: NZXT Source 210 (Black) ATX Mid Tower Case.  Cheap, NZXT.

PSU: EVGA 600B 600W 80 PLUS Bronze Certified ATX12V / EPS12V Power Supply.  Budget PSU with decent components.

OD: Lite-On iHAS124-04 DVD/CD Writer.  Typical stuff.

OS: Microsoft Windows 7 Home Premium SP1 (OEM) (64-bit).  Cheapest, decent OS.

Monitor: LG 22EN43T-B 21.5" Monitor.  Cheap monitor.