I installed ubuntu 11.04 yesterday and I can only use ubuntu classic with no effects, because when I go on the normal ubuntu it flickers and stuff. My card is intel 82865G. I have tried adding i915 modeset or something to the grub but it makes my resolution REALLY small. I don't know what to do. This never happened in 9.10 10.04 or 10.10.
You can do one of these, or both:
Add this PPA:
Or Downgrade Compiz to it's previous version as explained here, by doing this Unity won't be available anymore though.