The About Parallels Workstation window provides information on Parallels Workstation version and build you use, full name of the vendor and link to its site, copyright and trademark information. All are located in the top of the screen. License information and current status of several system settings are displayed below.
Active Copy
If you have an active copy of the Parallels Workstation, About screen looks as follows.

License Information
User Name and Company Name contain information about your name and the name of your company that your entered when installing the Parallels Workstation (in Windows) or in Activate Product window (in both Windows and Linux primary OSes).
Product ID displays identification number of your copy of the Parallels Workstation where the following information is encrypted: version of the Parallels Workstation, license number, and the abilities covered by your license that are displayed in Primary OSes and Terminal Services fields.
Validity period shows the date until your license is valid.
Primary OSes indicates which primary operating systems are allowed by your license.
Terminal Services displays which primary operating systems are able to access Parallels Workstation remotely.
Note: The same license information is displayed in the Activate Product window. See Activating Parallels Workstation in Windows or Activating Parallels Workstation in Linux.
Additional Information
This group contains indicators that are active only when guest OS is running. Otherwise they are off.
Virtualization mode shows Intel VT-x if you work on Intel VT-enabled processor and Virtualization Technology is activated through Virtual Machine configuration setting available on the VM Flags tab of the General Options. See Intel Virtualization Technology (VT-x) Support for description of VT-x.
If you run without Virtualization Technology, virtualization mode indicates acceleration level. All guest OSes besides Windows NT/2000/XP/2003 run in Software mode 0. Windows NT/2000/XP/2003 start with Software mode 0, then switch to Software mode 1 and Software mode 2 in case Acceleration Level setting (on the VM Flags tab of the General Options) is set to High.
Remote client session indicates if the Parallels Workstation is executed on a remote server.
Citrix support active indicates whether Parallels Workstation is executed on a remote server under Citrix Metaframe with Citrix support turned on. See Citrix Support topic for additional information.
Inactive Copy
If you have not activated you copy of the Parallels Workstation or your license is expired, License information group displays relevant information.
In Windows primary OS:
Depending on whether you had previously received a trial activation key or not, Evaluate and/or Buy buttons are available at the bottom of the window prompting you to get a trial or a permanent activation key. See Activating Parallels Workstation in Windows for detailed description of the processes of receiving a key and activating.
In Linux primary OS:
Depending on whether you had previously received a trial activation key or not, warning text contains one or two links prompting you to get a trial or a permanent activation key. See Activating Parallels Workstation in Linux for detailed description of the processes of receiving a key and activating.