Using KVM, one can run multiple virtual PC:s, each running unmodified Linux or Windows images. Each virtual machine has private virtualized hardware: a network card, disk, graphics adapter, etc.
KVM (for Kernel-based Virtual Machine) is a full virtualization solution for Linux hosts on x86 hardware with x86 guests. KVM is intended for systems where the processor has hardware support for virtualization. All combinations of 32-bit and 64-bit host and guest systems are supported, except 64-bit guests on 32-bit hosts.