"settings" from "start" menu is missing.

There are Registry hacks that will remove Printers, Control Panel and the Taskbar controls from being visible under Settings. The interesting part is that, "Removing the Taskbar, Control Panel, and Printer folders causes the Settings menu to be removed completely."
So, perhaps that is what is going on with your system.

Open Regedit and look for the following registry entries:
For Taskbar hiding
Key: [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
Policies\Explorer]
Value Name: NoSetTaskbar
Data Type: REG_DWORD (DWORD Value)
Value Data: (0 = disabled, 1 = enabled)

Hide Printers
Key: [HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\
Policies\Explorer]
Value Name: NoPrinters
Data Type: REG_DWORD (DWORD Value)
Value Data: (0 = disabled, 1 = enabled)

Hide Control Panel
Hive: HKEY_CURRENT_USER
Key: Software\Microsoft\Windows\CurrentVersion\Policies\Explorer
Name: NoSetFolders
Type: REG_DWORD
Value: 1

Hope this helps.