I know nothing about motherboards - if people think this thing doesn't have the right motherboard or whatever, then someone more technical than me needs to chip in.
But . . . otherwise, try this link:
http://www.compusa.com/applications/searchtools/item-Details.asp?EdpNo=4348627&sku=S445-10007&SRCCODE=COMEM210TT&cm_mmc=Email-_-Main-_-COMEM210-_-text It's a reasonably powerful desktop for only $420, including dual 2.5 ghz core processors, 4 gb ram, 2 lovely open firewire ports, and 2 or 3 open pci slots. The sound card is crap, but you should disable it and use some nice external device - at least when you can afford it because that is going to run $150 or more. Another thing to save your pennies for is a big external hard drive with firewire or usb 2.0 connectivity and 7200 or faster (the Seagate xtreme 1.5 tb firewire drive is about $180). Also, you will need to buy a monitor, but you can get a decent 17-20" flatscreen these days for under $100.
Specs are:
Condition: Refurbished
Lifestyle: Home & Student
Operating Systems: Windows Vista Home Premium 64-bit
Startup Operating System: Microsoft® Windows® Vista Home Premium 64-bit
Platform: PC
Orientations Allowed: Vertical
Form Factor: Minitower
Bays: 2 - 5.25" Drive Bays
Internal Bays: 6 - 3.5" Drive Bays
Available 3.5" Drive Bays: 4
Available 5.25" Drive Bays: 1
PCI Slots (Total): 2
PCI Slots (Available): 1
PCI Express X1 Slots (Total): 1
PCI Express X1 Slots (Available): 1
PCI Express X16 Slots (Total): 1
PCI Express X16 Slots (Available): 1
Expansion Slots: 4
PS/2 Keyboard Connectors: 1
PS/2 Mouse Connectors: 1
Serial Communication Ports: 1
USB Ports: 6
FireWire Ports: 2 x 6-pin
LAN Ports: 1
Audio Out Jacks: 5
Line In Jacks: 1
Microphone Jacks: 2
Processor Brand: Intel
Processor Class: Pentium Dual Core
Processor Number: E5200
Processor Speed: 2.50GHz
Processor Interface: Socket 775
Processors Supported: 1
Processors Onboard: 1
Additional Technologies: Intel® Extended Memory 64 Technology
Dual-Core Technology
Memory Type: DDR2
Memory Size: 2x2GB
Total Memory: 4.0GB
Memory Speed: DDR2 800 (PC2-6400)
Memory Slots (Total): 2
Memory Slots (Available): 0
Interface: SATA II
Capacity: 640GB
Speed: 7,200RPM
Interface: SATA
Optical Drive Type: SuperMulti DVD±RW Dual Layer Labelflash
Optical Drive Class: DVD SuperMulti
Type: Media Reader
Capacity: 15-in-1
Audio Description: Integrated Audio
Audio Chipset: High Definition
Channels: 7.1
Graphics Description: Integrated Graphics
GPU/VPU: NVIDIA GeForce 7100
Video Memory: up to 256MB Shared Memory
Video Interface: HDMI
VGA
Communications Description: Integrated LAN Support
Interface Type: RJ-45 - Ethernet Connector
Data Transfer Rate: 10/100/1000Mbps LAN
Communications Description: 56Kbps PCI Modem
Interface Type: RJ-11 - Phone Connector
Power: 300 Watt
Mouse Type: Optical
Buttons: 3
Connection Type: USB
Keyboard Type: Multimedia
Connection Type: PS/2
Connections: USB Powered
Front Speakers: 2
Height: 16.34"
Width: 7.09"
Depth: 17.32"