If you only want to dedupe by one column and not by entire row, select the column which has the duplicate entries, goto Data > Filter > Advanced Filter, check "Unique records only." and hit OK. It will filter in place, then you can copy and paste everything in to a new sheet and you'll have only unique records by the column selected. If you want unique data by the entire row, just select all of the colums in the first step.
The opposite of what you asked for, really, but you should be able to still get the same results with a little work.
I hope that makes sense, I haven't finished my coffee yet.