This paper describes Harmony-a grid infrastructure built using personal computer resources. Harmony addresses the key concerns of end users for responsiveness, privacy and protection by isolating the grid computation in a virtual machine on the PC. Harmony also addresses the key concerns of enterprise IT by automating the configuration and deployment of grid services and by automating the workload management so as to meet quality of service goals. Harmony's layered resource management architecture diverts grid workload to currently under utilized desktop resources. Harmony is designed to handle transactional workload - a key characteristic of commercial applications. Our implementation is Web Services-based, so the programming model of Harmony is compatible with and familiar to enterprise developers. We believe that Harmony demonstrates practical exploitation of a hitherto underutilized resource of considerable capability, with the potential to complement, or even in some cases replace, dedicated server-based resources.