The Web Sharing tab only appears with Internet Information Server (IIS)
installed.  The Web Sharing tab allows you to share the volume on a Web
site.

Folders Security tab

To display the Security tab...
Open Folder Options in Control Panel.
Click Start, point to Settings, and then click Control Panel.
Double-click Folder Options
On the View tab, under Advanced settings, clear: Use simple file sharing
[Recommended].

Use simple file sharing [Recommended] means...
[[Specifies that simplified sharing is enabled. Simplified sharing lets you
share folders with everyone on your workgroup or network and make folders in
your user profile private.  However, if simplified sharing is enabled, you
cannot prevent specific users and groups from accessing your shared folders.
Clear this check box if you want to set folder permissions for specific
users and groups.]]

[[Note You cannot turn off simple file sharing in Microsoft Windows XP Home
Edition.]]

[[If simple file sharing is enabled, you see the simple file sharing user
interface appears instead of the Security and Sharing tabs.  By default,
this new user interface is implemented in Windows XP Home Edition and in
Microsoft Windows XP Professional if you are working in a workgroup. If you
turn off simple file sharing, the classic Security and Sharing tabs appear,
and you can specify which users and groups have access to shared folders on
your computer. ]]

How to disable simplified sharing and set permissions on a shared folder in
Windows XP
http://support.microsoft.com/kb/307874

Open Group Policy...
Start | Run | Type:    gpedit.msc    | Click OK |
Navigate to...
Administrative Templates\Windows Components\Windows Explorer\
Remove the Security tab
Set to Not Configured or Disabled.

Remove the Security tab
[[Removes the Security tab from Windows Explorer.

If you enable this setting, users opening the Properties dialog box for all
file system objects, including folders, files, shortcuts, and drives, will
not be able to access the Security tab. As a result, users will be able to
neither change the security settings nor view a list of all users that have
access to the resource in question.

If you disable or do not configure this setting, users will be able to
access the security tab.]]

Check settings here...
HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
Policies\Explorer
and/or
HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\
Policies\Explorer
If there is no NoSecurityTab listing then this is not the problem.
Value Name: NoSecurityTab
Value Type: REG_DWORD
Value Data: 0 or 1
0 = Security tab will be visible
1 = Security tab will not be visible
------------

The sharing tab is not visible if you are logged on to a machine with an
account that does not have adequate rights.

The sharing option is not available for the Documents and Settings, Program
Files, and WINDOWS system folders.  In addition, you cannot share folders in
other user's profiles.

or...

The Sharing tab is not visible....
Start | Run | Type:   services.msc    | Click OK |
Scroll down to and double click:  Server service |
Set Startup type to: Automatic | Click Apply | Click the Start button |
When it has started, click OK

If you do not see the Server service..........
This will restore the Server Service (lanmanserver).

Open Network Connections, click Start, point to Settings, click Control
Panel, and then double-click Network Connections.  | Right click Your
Connection | Properties | General tab | Install button | Highlight: Service
| Add button | Highlight: File and Printer Sharing for Microsoft Networks |
OK | Close