My initial reaction when I first saw your photo is that it is Straggler Daisy, aka Horseherb, although I am not sure the leaves look exactly the same as horseherb's. i've been pondering it though, and I cannot think of anything else that has those tiny yellow flowers on plants with leaves that size and which grows very densely like a ground cover. I'll link horseherb for you below, and again, I am not sure yours is horseherb, but I'm thinking that if it isn't horseherb, it might be related to it somehow.

Here is a link that might be useful: Horseherb Info from NPSOT

Oh thanks Dawn I think that's it!
It does have runners and grows pretty dense even crowding out most grass and weeds. I have left a few splotches of it in the corners but I am going to try to move some around front this fall, where its a little too shady for anything else.
I found something on the web but the flower wasn't right like this
kim