Sorry for not writing an essay before. I've been through that with Dell and am all talked/ typed out. I've been trying to pick up bits of info from forums, and read all this stuff about wattage and power--that's one reason I hesitate to just buy any card without more information. If it's possible to short out my computer, I mean to avoid doing it.
Here's the story:
Like you said, the PC came with an ATI Radeon HD 4200. There's only one 15 pin connector on it. Dell told me that to enable extended monitors, I'd have to buy a different card. They suggested the second dual monitor card--the ATI Radeon 64MB PCI. That one has the two connectors you mentioned. The problem is that both monitors show identical images. They both identify as "Monitor 1." So the computer only picks up one signal from the two monitors. Under the "screen resolution" tab, there's no option to switch to two monitors.
One of the Dell techs even did a remote assistance. He disabled the old card and tried at least 6 different drivers on the new card. None of them fixed the two monitors, including the Catalyst drivers. Dell told me they think the card is a lemon, but also that they won't replace it. (They said that by the time I hooked up the computer, a warranty had expired. That's another story.)
I did more research, and the Microsoft website lists the card as questionable with Windows 7, not compatible. The box the card came in lists XP as the most advanced system it supports, but I bought it from Dell without seeing the box.
So are you saying that any card with two ports is more or less okay, assuming it's Windows 7 compatible? What about the wattage and power of my PC? How would I find that out, if it's important? I don't want to pick up something that will give me a whole new problem.
Anyway, thanks for your help. This is my first home dual monitor setup. I don't want to kill my computer.