I'm not sure if Dell's computers (their power supplies) are compatible with other motherboards. And their cases might even be shaped differently than a regular motherboard. IE, you wouldn't be able to screw the new motherboard in quite right...

You might have to pretty much consider building a new computer, unless you can get a replacement motherboard and CPU that are the same as the ones you broke. You can get a pretty nice upgrade for around $500 if you know what to look for and can build it yourself without messing it up like you did to the parts above.

But at your computer store, if you want them to build it, prepare to have them recommend you over $700 in computer upgrades - when my ~$500 of upgrading would probably be more than you need anyways and "on par" (if not higher quality than) with their recommendations. I dunno, I am kind of a killer of local economies with my depending on reliable and cheap Internet sources -- and the way I point people to them I'd probaby go out of business if I decided to get into computer work and kept telling everyone where to get stuff cheap