Limit Access to Local Computer with Internet Explorer 4.01

• Microsoft Internet Explorer version 4.01 for Windows 95
• Microsoft Windows 95
• Microsoft Windows 95 OEM Service Release 1
• Microsoft Windows 95 OEM Service Release 2

IMPORTANT: This article contains information about editing the registry. Before you edit the registry, you should first make a backup copy of the registry files (System.dat and User.dat). Both are hidden files in the Windows folder.

SUMMARY

This article describes how to limit access to hard disks on computers running Internet Explorer 4.01 with Windows 95, Windows 95 with Service Pack 1, Windows 95 OEM Service Release 1, or Windows 95 OEM Service Release 2.

MORE INFORMATION

WARNING: Using Registry Editor incorrectly can cause serious problems that may require you to reinstall Windows 95. Microsoft cannot guarantee that problems resulting from the incorrect use of Registry Editor can be solved. Use Registry Editor at your own risk.

NOTE: For information about how to edit the registry, view the Changing Keys And Values online Help topic in Registry Editor (Regedit.exe). Note that you should make a backup copy of the registry files (System.dat and User.dat) before you edit the registry.

To limit access to the local workstation, set the DWORD value NoRun to the value 0x1 in the following registry key:

   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\
      Explorer

Setting this value also disables the ability to browse to the local file system using an embedded HTML link. For example, you cannot browse a file by clicking the HTML link provided by the <a href="file://c:\">My File System</a> tag when this registry setting is used.

If you want to disable access to a drive altogether, set the DWORD value NoDrives as indicated in the following table:

   Drive   DWORD value
   -------------------
   A       0x1
   B       0x2
   C       0x4
   D       0x8

   HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\
      Explorer

This logic uses a bitwise left shift to decide which drive to use. For example, if you want to disable viewing drive C, set the DWORD value to binary 0100. The code takes the return value from the function, subtracts "A" from the value, and shifts the binary value left by that number of bits.

For example, drive C - drive A = 2. 0001 shifted to the left twice is 0100. Binary 0100 has the hexadecimal equivalent of 0x4. This is how you calculate the drive to disable.

As another example, if you want to disable drive N, use the following method to calculate the hexadecimal value to place in the registry:

1. Determine the numerical placement value for the letter N. If A=1, B=2, C=3, and so on, then N=14.

2. Subtract the numerical placement value for A from N (14-1=13).

3. Left shift binary 0001 by 13. This becomes a binary number with 13 zeros following a 1 (0010 0000 0000 0000).

4. Convert to hexadecimal: 0x2000.