To make a backup copy of a virtual machine created with VMware, just copy the folder to another location. When you power on the copy (open the VM), you will be asked if you have moved the virtual machine or copied it. Select that you "Moved It". This will keep all of the settings the same. If you select the "Copied It" option, a new UUID and MAC address will be generated, which could cause Windows Activation to come up and can also cause Linux machines to have problems with the Ethernet devices.
You will not be able to use a backed-up virtual machine at the same time as the original because you will have a MAC Address conflict on your network. If you need to be able to run the backed-up virtual machine at the same time as the original, you should make a copy using the "Copied It" option.