You can get Service Pack 3.0 for Windows NT 4.0 from the Microsoft FTP site at ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/. An alternate Microsoft site is ftp://18.104.22.168/fixes/
At either site, navigate to the country/product/ServicePack/Processor directory and choose the Service Pack .exe file, not the symbol file. The U.S.A. Service Pack for Intel processors would be at usa/nt40/ussp3/i386/. You must download and read the release notes which is the 59KB readme.txt at the Microsoft site. Click here or here for the U.S.A. readme.txt. Click here or here for the U.S.A. NT 4.0 Service Pack 3 for Intel Processors.
If these sites are busy, you can click here to download a zipped U.S.A. release notes file.
Service Pack 3 alters the ERD (Ermergency Repair Disk) process. You must create an ERD by running RDISK /S after you successfully reboot from an SP3 install (always keep multiple generations of the ERD and keep your last SP2 ERD until you are sure all is ok). To use the ERD after SP3 is installed, you must update Boot Floppy 2 of the 3 diskette boot set. Copy the Service Pack to a temporary directory, switch to that directory and type the service pack /x Example: nt4sp3_i /x Copy Setupdd.sys from the expanded Service Pack to boot floppy 2 of the 3 diskette set. It will replace the older version. If you ever recreate the boot floppies by running Winnt /ox or Winnt32 /ox from the CD-ROM, you must repeat this process.
Due to changes in the Registry Security Hive, the SAMSRV.DLL, SAMLIB.DLL, and WINLOGON.EXE have changed and previous versions of these files cannot access NT system security information. If you unistall SP3 these files will remain. Do not replace them with older versions.
Be sure to check for POST-SP3 HOTFIXes at ftp://ftp.microsoft.com/bussys/winnt/winnt-public/fixes/
For quick access to the KB articles mentioned in the readme, click below:
For a KB article on new features, see Q165333
NOTE:It is best to uninstall SP2 or SP3 prior to an update install. If you have RAS installed you must uninstall the SP. If you can not uninstall, then:
expand <cd-rom>:\i386\tcpip.sy_ %systemroot%\system32\drivers\tcpip.sys prior to doing the update install. The note is also applicable to installing RAS after SP2/SP3.