12.10 problems black screeb

[Grizzly]

Just trying out 12.10 (32bit Desktop) trial LiveUSB\

boots eventually
desktop screen background shows but no menus or icons (just the red swirly 
pic)
network disconnected pops up
Ctrl+Alt+Del brings logout dialogue
PrtScr brings ScreebGrab dialogue
E-mail button brings up Thunderbird email settings
Volume up down buttons work as expected

AFAICT no other Keyboard shortcut does anything
Loging out brings a login dialogue & limited top right menu

any ideas what went  wrong and how to get it working