Got it Wrench is the modeling room?

A few things first. 

What kind of object do you have selected when you go from the assembly room to the object room if anything or the whole scene? 
Is it a primitive you created or something you have imported or placed from the content window?

One thing that might be helpful is to have a screen shots of the assembly room with the object selected and then whats happening in the modeling room so we can see whats going on.