screen resolution not changeable

[michael]

Hello,

Ijust upgraded from Ubuntu 7.10 to 8.04. When restarting I was in a kind
of restricted mode which suggests me to select a graphic driver. But
this doesnt help. So I used Envyng to install the my ATI drivers. Then
the boot was ok, the screen has a resolution of 1280x800. But I have
still some problems with display/graphics/drivers.

1.If I want to change the screens resolution I get:
	The X Server does not support the XRandR extension.  Runtime
 	resolution changes to the display size are not available.
Why this?

2.I don't see the ATI driver in the restricted drivers menu.
Is it still not installed somehow?

3. The overall performance its now very poor, I guess thats also linked
to that graphics driver mess.

Who can help me?

System:
Notebook 
Ubuntu 8.04
ATI Radeon X1400

Thanks Michael