This article was previously published under Q132545
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The Special Step-Up Edition of Windows NT 3.51 can be used to upgrade fromWindows NT 3.5 to Windows NT 3.51. The Special Step-Up Edition runs only oncomputers with Windows NT 3.5 or Windows NT 3.51 installed. If Windows NT3.5 or 3.51 in installed on a computer, you can use the Special Step-UpEdition to upgrade that copy to Windows NT 3.51, or install Windows NT 3.51into a new directory. The Special Step-Up Edition cannot be used to upgradeor install over Windows NT 3.1.
NOTE: The Windows NT repair procedure also uses these steps to detect aWindows NT installation to repair. If NTOSKRNL.EXE and NTDLL.DLL arecorrupted, the repair process may fail reporting it cannot locate a WindowsNT installation. It is possible to expand and copy NTOSKRNL.EXE andNTDLL.DLL to the %SystemRoot%\System32 directory to allow the repairprocedure to continue.
The Special Step-Up Edition setup program checks the following to verifythat an upgradable copy of Windows NT 3.5 is installed on the computer:
The BOOT.INI file is searched for entries indicating installations of Windows NT.
Setup checks for the following files and directories in the location specified by the BOOT.INI entry:
Setup loads the SYSTEM and SOFTWARE hives from the registry and verifies the product type and version. The following items are verified in the registry:
The installed version must be 3.5 or higher, but not higher than the version you are attempting to install.
The installed version product type is compared against the Step-Up product type. You cannot use the Special Step-Up Edition of Windows NT Workstation to upgrade a Windows NT Server installation, and vice versa.
If all of these things check out correctly, Setup proceeds. If any of theelements listed above are missing, the Setup does not to proceed. Also, ifanything prevents Setup from seeing the Windows NT 3.5 installation, Setupdoes not proceed. For example, mirrored drives, inaccessible drives, andother similar problems can prevent Setup from seeing a Windows NT 3.5installation.
Windows NT 3.5 and Windows NT 3.51 Setup use the same steps listed abovewhen looking for previous installations of Windows NT. The onlydifference is, the Special Step-Up Edition setup program requires thepresence of an upgradable copy of Windows NT 3.5.