If you do not have a recent Intel or AMD x86 processor that supports these virtualization technologies, you still can use QEMU with virt-manager, but you will lack the accelerated support. Owners of processors with Intel Virtualization Technology (VT) need to make sure the kvm-intel kernel module is loaded otherwise load the module manually. Likewise, owners of processors with AMD-V technology need to ensure kvm-amd is loaded. Once you are set to roll, you can launch virt-manager and then proceed to create a new virtual machine. When launching virt-manager connect to the localhost or a remote virtualized machine and use QEMU as the Hypervisor.
The first thing to do when creating a new virtual machine is to name the system using only alphanumeric characters. For our purposes, we had called the system winxphome when virtualizing a copy of Microsoft Windows XP Home Edition. The system name is only used for identifying the system in the Virtual Machine Manager and the name must be unique.