Windows 7: Unable to save display settings - Laptop - ATI Radeon Xpress

I have just upgraded a Toshiba Laptop from XP to Windows 7 32 bit.
Everything seems to work fine "except" the ability to use dual monitors.
I had "another" secondary monitor connected with XP and it worked fine.
Now I am using a Dell E178WFP 17" (I don't believe it's a monitor problem).
I can get it to see the secondary and I can switch to it but it won't extend.
When I select "Extend" and apply, it says "Unable to save display settings".

I have gone to Windows Forums and read an older post.
The answer was to navigate in Regedit to:
HKEY_CURRENT_USER\Software\Microsoft\MobilePC\TMM
and delete the subkey, but.......
There is no such folder as MobilePC in Regedit when I go to that location.
That post assumes that the configuration detects the old secondary monitor and thinks that I am attempting to install a third monitor on this laptop.
It says that I need to clear the multiple monitor configuration for the laptop in order to extend.
But the proposed solution won't work due to the reason stated above.
I have tried a number of things with no resolution to the problem.
I'm stumped!
I'd appreciate any help.



Thanks,
Jim

PS: I have updated the integrated video (ATI Radeon Xpress), BUT I still get "Unable to save display settings".