is it objects u jus pasted or you pasted and merged down... if its the second senario you cant move it by its self once merged so you just keep on pressinc ctrl+z to undo till the layer u pasted is detatched. it its the first senario just listen to AL... he knows what he is talking about here
Maybe you mean text? Sometimes that's hard to move. To make it easy just click the text layer and then click move the current layer (while having the move tool selected) on the tool bar dialog. It's on the picture I posted above below pick a layer or guide
the trick with text, to put it much shorter (sorry AL) is to click on the letters of the text w/ the move selections tool. if u fail just use ctrl+z (my favorite button combo)