How to enable compiz-fusion?

My system:
Intel based Dell latitude d620 (Core 2) with 2Gb Memory

I had compiz-fusion up and running ones with a nice cube that reflected on the surface. So I know it should be possible again. But I have read so many forums posts/wikis/howtos that I got lost.

Also tried CF_installer but failed too.

I lost my compiz after playing with xinerama to enable a second lcd screen (which worked too but without compiz) I tried to get this done too but it got messier every day.

So what are the steps to get me back on track? I think I disabled removed all compiz from my system now at least.

I have the feeling I just needed to enable disable a few things in my xorg but I have to clue what it should be. OpenGL is not wotking like it should be. Is the i810 driver still the one?

Who can help?