Why do 16-bit programs no longer run on a Windows 2000 system after I install Service Pack 2 (SP2)?

A. Win2K SP2 introduced a program compatibility feature in the Windows NT Virtual DOS Machine (ntvdm.exe) that can prevent some 16-bit applications from running. If you receive the following error message, your program is experiencing this known problem:

<Program> caused a General Protection Fault in module KRNL386.EXE at 0001:6382 
Choose close. <Program> will close.

To resolve the problem, perform the following steps:

1. Start a registry editor (e.g., regedit.exe).
2. Navigate to the HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\AppCompatibility\NTVDM.EXE subkey, then press Delete.
3. Click Yes to the confirmation.
4. Restart the computer.