Here is a great article by Lifehacker on Mojopac which is an application that lets you take your applications with you and run them on a different computer. Neither on windows nor on linux this is a trivial feat: programs nowadays write config files and libraries/dll all over the place. Since this does not look like a full virtual machine and it only “emulates” windows under windows, I guess it just intercepts all the calls from certain programs to the file system and the registry and redirects them to the virtual disk it creates. I guess it’s more similar to SandboxIE (i.e., an application sandbox) than to VMware.