I have two of the same objects. Now i moved object 2 lets say...how can i move it back to the same location and size of object 1 ? is there any way to copy this from object one to object 2 ?
There are various ways.
I would use the align tool.
Select object 2, then Shift select object 1. (The last one selected becomes the one whose position in space is used.) Go to Object/Transform/Align Objects, then at the bottom of the tools column, highlight X, Y and Z by holding shift down while selecting the second and third axis.
If you've been doing things with these objects that could result in their origins being moved, you should first go to the Tools tab of the Tools editor, while in Object Mode, and set Origins to Geometry for both objects.
As for the size, I'm not sure what you mean. If they were the same size originally, but one has been scaled, of course you could just read off the scale of one and type it into the scale values of the other.