I have a VM using Hyper-V on Win Server 2008. I'm using the "Now" snapshot, I want to merge everything so I have only one VM with no snapshots.
The short answer is to delete each of the snapshots (The one from 1/2010 and 6/2012) and then shutdown your VM. Hyper-v will merge the AVHD files into the original parent VHD and you will have just the one VHD file at the end.
However ... there are a few things you need to be aware of.