Windows Server Backup
Windows Server Backup provides a basic backup solution, and is very popular and effective especially for smaller businesses looking to save money. It comes with Windows Server 2008, and is particularly easy to use, so you don't need a network administrator to perform backups and restores.
You can Windows Server Backup to back up Hyper V virtual machines, but you have to do a little work first. The first thing you have to do is register the Microsoft Hyper-V VSS writer with Windows Server Backup. This can be done in one of two ways.
You can do things the old fashioned "hands on" way, and follow the steps in this Microsoft knowledge base article.
Microsoft has created a "Fix it for me" program file that you can download here or by going to the Microsoft knowledge base article linked above, and finding the download link there.
Once that operation is complete, you can create a backup within the host operating system using Windows Server Backup.
Be sure to back up not only the VHD image files, but also any configuration files that the image requires to run. They aren't always on the same partition. If you're not certain where all the files you need to back up are located, consult the network administrator or the person who created the Virtual Machine.
Also, be aware that Windows Server Backup does not support backing up Hyper-V virtual machines on Cluster Shared Volumes (CSV volumes).