Graphics on a new mobo

They do exist for Socket 939 motherboards, but that socket is already the previous generation and the boards that did have both were low-end motherboards. So not really.

I've heard of converters but also heard they don't work too well - bad performance and compatibility issues. I'd also expect they cost more then its worth. A Radeon 1600 Pro or equivalent card will be pretty cheap a year from now.

Certain socket 775 boards support dual core processors and certain one's don't - it depends on the chipset. All socket 939 boards support the dual core's but the NForce4 chipset based boards have issues with USB transfers when using a dual core processor. All Socket 940 boards support dual core processors as well. Socket 754 boards only support single core processors.

940 is currently the newest, key word there is currently.

ATOP bridge: http://www.techpowerup.com/?3272
But only for Nvidia FX and 6xxx series cards.

Nope.

Sell it, return it...

I don't know, check eBay. Many places do take back opened items.

I think your best bet is to sell it someone who needs one or sell it on eBay.

You can get boards of any size, but its the case that'll determine it if takes a standard PSU or not, but most are standard. Micro-ATX boards fit mid and full ATX cases but you won't fit an ATX board into a micro-ATX case, you also should be aware that bigger cases are generally better for cooling.