If you are trying to install a Classic Product in any virtual environment (VMWare, Virtual PC, Parallels, etc.), you can not use stand-alone (single) Activation codes.After 30 days, if the product is unable to validate its license via Internet, the license is removed from your computer.Validation is performed in the background and no user intervention is required unless the program cannot communicate with On Center's licensing servers. After the first activation, and at approximately 30 day intervals, an Internet connection is required to validate the license. An active Internet connection is required to activate your license.