Motherboard Replacement for 2007 Dell X420

[BC5005]

I really need to upgrade the motherboard on my 2007 Dell X420. I'm looking to find something that for the most part would be compatible or backwards compatible. I believe the Dell has an oversized power supply. It uses DDR2 ram. It would be nice to be able to use either DDR2 or DDR3. It is a full size AXT mobo. I have a Haupauge 2250 card in it. It is used in conjunction with a BenQ projector that has an HDMI connection, 1080p and 3D ready. It also has a card to allow dual monitors. I think there are some compatibility issues with Vista Ultimate and the board has to be replaced to upgrade to Win 7. The replacement mobo als needs to have a LAN and WiFi connection capabilities. The graphics card was replaced less than 6 mos ago with an MSI R5450 MD1GH. Recommendations are certainly appreciated.

 

[13thmonkey]

nothing modern uses DDR2.

 

[Calvin7]

I would buy a bare Mid-Tower PC case that has good cooling (140mm fan(s) on top, two 120mm fans up front).
Get an ATX size motherboard.
Reuse the TV Tuner
WiFi might be more convenient using an add-on card or USB.
You might be able to reuse the power supply.

Intel would be the best and most expensive.
AMD would be cheaper. Their FM2+ motherboards may be the lowest price.

If you are planning on reusing the old CPU, then eBay might be the place to look for used parts.