Shift + Command + S Shortcut Not Working

When I press the Shift + Command + S keys in Preview or Pages or other applications, it does not present the "Save As" drop down. I can access it with the mouse by clicking on "File" "Save As". It does work with the shortcut key if I log in as a different user.
I have exhausted my research on this including following the instructions given to me by Apple on phone support.
Can you help me?
Thanks
Steve

OK. Bin playing
On my keyboard MBP US.
If the s key is held down before the shift & command keys it doesn't work..
Hold down the shift & command keys before the s key and it works fine.

I wish it were that simple.

But thanks for the reply.

It's Fixed!

The problem where the Shift + Command + S did not invoke the "Save As" command in my applications was a nightmare. 2 days of searching, a trip to the Apple Genius, and a phone support from Apple tech did not resolve the issue.
Thanks to hayne and Mac OS X Hints Forums (Command-Shift-s opens Safari - can't reset - The macosxhints Forums.
My issue was resolved when I removed the loginwindow.plist file which apparently controls the applications that load at startup per user account. I had 10 different applications starting. When I removed the file, the new file had no applications listed and my shortcut key combination started working again. I didn't care to narrow it down to which application was causing the problem because I shouldn't be starting all those programs anyway.
Thanks again!