Missing Security tab despite turning off Simple File Sharing

[eureka]

I cannot see the Security tab I should see when I right click a folder and click
Sharing and Security.  I am using Windows XP Progessional (SP2).  My computer is not part of a network. I share my computer with a friend. I have got an administrative account and have created a normal user account for my friend. My aim was to restrict my friend from accessing some of my folders. However, since I cannot see the security tab I am unable to do so.

I have tried the following so far but nothing has worked:
-  I have Windows XP Professional (SP2)
-  Its a NTFS Filesystem
-  I have switched "Simple File Sharing" off
-  I'm logged in as an Administrator
-  I have checked the Server service (uninstalled and reinstalled
  it)
- I Read on another forum to do the following:
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.

However, I cannot see Windows Explorer under Administrative Templates\Windows Components\ in group policy.

Please help!! I've spent hours Goggling and I just keeping
getting the same advice to turning off simple file sharing. 

[Broni]

Open Registry Editor.
Navigate to:
HKEY_CURRENT_USER\Software\Microsoft\windows\CurrentVersion\Policies\Explorer
and see, if you have a key Nosecuritytab
If it's there, and a value of it is "1", change it to "0"

[eureka]

I haven't got a key Nosecuritytab in HKEY_CURRENT_USER\Software\Microsoft\windows\CurrentVersion\Policies\Explorer

[Broni]

Are you using NTFS?

[Broni]

If you have Windows XP CD, run:
sfc /scannow

[eureka]

I tried running sfc /scannow but it didn't work.

[Broni]

Are you using NTFS?

[eureka]

yes, I am using NTFS Filesystem

[Broni]

Check, if security tab is present in Safe Mode.