I am kinda new here, so this would be my opinion. So don't take it to heart, I would listen to a more experienced user more or less, but this would be the determining fact for me.
I wouldn't be as much worried about it working with my mobo, but more or less if it would fit in my case, usually store bought PCs really don't have any room to upgrade (unless your talking about ram, or the basics), they like to "conserve" space with there tiny cases.
Now if it would fit, I was looking around and this is what I found http://www.highpowersupply.com/produ...pc420102df.htm
Now my board is a ATX20 and then I have a separate 12v 4 pin connector, your board pretty much has them all set for one spot, that connector from what I've read is to give the CPU more power, but in newer boards it can also give the Vid Card more power, more then likely the reason you want it.
From what that picture looks like, you just snap the end onto your connector if you have a 24pin setup like on your board. But from the picture of the PSU you are looking at, from what I've read I'm not sure if the unit would snap together like that one in the link.
I suppose this wont help but I'll list this none-the-less, from what I can see on my PSU, they look like they would just slid right side by side if I did have a 24pin requirement. But then again this is theory, as I haven't built any pcs with a 24pin setup, all are 20 then a separate 4.
You might need to call, because it might have a sepearte non-attachable piece like on my PSU, it's completely sperate from the unit, like a whole different cord.
I'd also open your pc and check your area for the PSU, some companys set there pcs up in a manner in which they can only replace certain parts, in which case it might be just as cheap to buy a new case for 40$, I mean I've seen them really cheap, and they usually come with at least a 450watt psu, but watch the shipping on ebay, they are rip offs, you may pay hardly nothing, but the S&H will more then likely make up for there lose in the over all bid ratio.