sawfish blocks desktop

[Horst Seeger]

Sorry, I have tried to start Ubuntu 11.04 with Sawfish (through change 
in "login-screen"). Now it shows just violet background and UBUNTU. No 
Keystroke reacts, no mouseclick ist working neither combinations of it 
as explained in the Guideline under "Keybindings".
Now I want to remove it again to return to Ubuntu Classic or Unity. But 
how to do that?

The problem happened on my Netbook: Acer Aspire One
Help would be appreciated. Thanks

Horst Seeger