If you mean:
Right Click menu missing
http://support.microsoft.com/kb/555362
or the Sharing tab is missing. When you Rightclick a folder, then click on
Properties, the Sharing tab from the Properties box is missing. You are also
talking of shell extensions then this could be the problem. You can enable
the Sharing tab by enabling the "Shell extension for sharing"
You can use this utility:
ShellExView v1.40 - Shell Extensions Manager
http://www.nirsoft.net/utils/shexview.html
1. Scroll down for the download links. I prefer the ZIP file.
2. There is nothing to install, just double click on shexview.exe then wait
till all items are loaded.
3. Click the column heading "Type" to sort that column alphabetically.
4. Now under "Type" column all Context menus are next to each other.
5. Under the column "Extension Name", click "Shell extension for sharing".
6. Under the column "Disabled" No means the extension is enabled. If it says
Yes, click on the green button at the top left and click Yes to the prompt.
The action takes effect immediately without restarting.