if the same disk with 2 partitions you will have to delete the non OS partition then right click the win 7 partition and select 'Expand'
If you do that you will lose all data and files in the non-OS partition. First, copy/move them all into the Win 7 partition.
Do any of you know the technical reason it isn't easy to just merge partitions? It seems like it should be a fairly simple operation, but if it was easy, it would be easily available, eh?