HPFS and NT: Easy as A-B-C
Windows NT 4.0 does not support the High-Performance File System (HPFS) unless it was installed prior to upgrading. To add support for HPFS to a new NT 4.0 install, copy PINBALL.SYS from the NT 3.51 CD to WINNT\SYSTEM32\DRIVERS. Use RegEdit on an existing Windows NT platform that supports HPFS and export the key HKEY_LOCAL_MACHINE\SYSTEM \CurrentControlSet\Services\Pinball. Import that key into your system with HPFS and reboot.

Permanent C:
NT machines behave strangely with 16-bit programs that use the NT Virtual DOS Machine (NTVDM) if the C: drive is anything other than a fixed disk. If you use removable drives and your 16-bit programs refuse to run, make sure C: isn't a removable drive.

Sound Idea
Some PCI sound cards will run under Windows NT but occasionally distort sounds-especially when you sweep the mouse or do any thing else that occupies the CPU even briefly. To avoid this, reset the PCI latency settings in your computer's BIOS to either the default settings or a lower number.

What's Up, Dock?
Some notebook computers use a PCI bridge to link to a docking station. During installation, NT 4.0 can't detect devices in this type of docking station. However, the Hardware Abstraction Layer (HAL) in Service Pack 3 can detect devices across a PCI bridge. Copy the i386 directory from your NT CD-ROM to a local drive, rename or move all files that match the HAL*.DL? wild card and replace those files from Service Pack 3. Install Windows NT using the WINNT /B /S:<sourcepath> argument. argument.

IE 4.0 and FTP
Internet Explorer 4.0 intercepts FTP commands typed into the Start/Run command line. You can prevent this with a Registry edit. To do so, go to HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows \CurrentVersion\URL\Prefixes and delete ftp and ftp.values.

Stop STOP
A STOP error during boot is an unsettling sight. Fortunately, some of STOP errors have easy fixes. STOP c0000135 (Unable To Locate DLL) is seen when a critical system DLL gets trashed, whether through a virus or because of a malicious or clumsy user. If the file is missing from WINNT\SYSTEM32, you can copy it back from the original CD-ROM or another NT system.

Tune In Both Channels
PCs with dual PCI/IDE channels on the motherboard have problems with NT if only one of the two channels is turned on, because the driver won't run if it doesn't see both channels. If you have disk problems, check your BIOS settings to make sure both channels are active.

Spooler Tomfoolery
Sometimes a corrupted EMF (printer data) file uses 100% of a CPU and throws the Spooler into an infinite loop. Rebooting often doesn't help, because the machine tries to pick up right where it left of f. One way to get around this is to boot to DOS or an alternate NT install and delete the SHD and SPL files from the Spool folder.

Odd FAT Time Stamp
When you use FAT on an NT system, the time stamps on files in the FAT partition are rounded to the nearest 2 seconds. That means the time stamp is always an even number, even when you copy a file with an odd time stamp to a FAT partition.

You Wont Believe This One...
"During normal operation or in Safe mode, your computer may play 'Fur Elise' or 'It's a Small, Small World' seemingly at random. This is an indication sent to the PC speaker from the computer's BIOS that the CPU fan is failing or has failed, or that the power supply voltages have drifted out of tolerance. This is a design feature of a detection circuit and system BIOSes developed by Award/Unicore from 1997 on."

http://support.microsoft.com/support/kb/articles/Q261/1/86.ASP