usb not working and no poweroff at shutdown

[gerald]

Hi,

after using kde on suse for years I love the fresh and light feeling of
Ubuntu....

anyway i encountered two problems on my machine ("medion" desktop PC
with SiS chipset):

1. my usb devices (memory stick and a webcam) seem to be not recognized
at all; (nothing under 
2. After Shutdown I just get the message "acpi power off called", then i
have to press the power button for 10 sec. to turn power off :(

I downloaded the ISO image for install and updated since then
regularly...

any ideas are welcome...
Gerald