I really only want to flog this topic so much.
I gave you my recommendation about the board. I have one, and the digital video is important to me. Perhaps it isn't to you, who knows.
As to if, or whether I'm willing to continue shopping for a board that costs exactly 49 dollars, I'm not.
At the end of the day, I believe that all the Gigabyte Intel G-41 chipsets are compatible with your CPU. At least they claim they are. If you would rather replace the board with a exact duplicate of the P-4's original home, which is an Nvidia chipset based board, that is a reasonable course of action also. Here again, I'm an Intel chipset in a Gigabyte motherboard person, and that would always be my personal preference.
The Nvidia chipset board is "deactivated" at Newegg, and that's where I buy all my parts, save for a Microcenter in my area. Personally, I'd rather not shop on Ebay. That's just an idiosyncrasy on my part. If you've had satisfactory dealings there, by all means, go for it..
With all that said, the shipping charge on the board at Ebay is ten bucks. That bring its price to 60 dollars anyhoo. The other board at Axion carries a shipping charge of $7.40, (UPS ground), and costs $53.95, so they're within pennies of each other in price.
No matter what you do, the memory from the Dell is not going to fit either one of the boards we're discussing, so that's potentially another expense to be reckoned with.