A method for replacing a current desktop image having a current operating system on storage media for a computing device is described. In the method, an agent process is executed on the computing device for downloading from a server to a staging area on local storage media a replacement desktop disk image having a replacement operating system. The replacement desktop image includes a prefetch set of files and metadata for additional files, the prefetch set of files including a minimal set of files necessary to boot the replacement operating system, the replacement desktop image not including contents of the additional files. The computing device is rebooted to replace the current desktop image with the replacement desktop image. The computing device is then rebooted again to load the replacement operating system using the prefetch set of files.