How to Determine Version of Windows Upgraded by Windows 2000

ID: Q231979

The information in this article applies to:

Microsoft Windows 2000 Professional

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, make sure you understand how to restore it if a problem occurs. For information about how to do this, view the "Restoring the Registry" Help topic in Regedit.exe or the "Restoring a Registry Key" Help topic in Regedt32.exe.

SUMMARY

This article describes how to determine the version of Windows that was installed on your computer before the computer was upgraded to Windows 2000.

MORE INFORMATION

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

For information about how to edit the registry, view the "Changing Keys and Values" Help topic in Registry Editor (Regedit.exe) or the "Add and Delete Information in the Registry" and "Edit Registry Data" Help topics in Regedt32.exe. Note that you should back up the registry before you edit it. If you are running Windows NT, you should also update your Emergency Repair Disk (ERD).

To determine the version of Windows that was installed on your computer before the computer was upgraded to Windows 2000, use Registry Editor to locate the following key:

HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\PrevOSVersion

When you click the PrevOSVersion key, values indicating the operating system, build, and other information is displayed in the right pane.

NOTE: This key is present only if the computer was upgraded from Microsoft Windows 95 or Microsoft Windows 98.

Additional query words:

Keywords : kbenv
Version : WINDOWS:2000
Platform : WINDOWS
Issue type : kbhowto