Search:

are you using the side drive bay or the internal one?

have you tried from a command line with a ls -al?

yeh, reboot ....it will not return anything to the console

try this from the command line: (if your running gnome)

rm -rf .gnome .gnome2 .gconf .gconfd .metacity

can you access the command line?

change http://my.yahoo.com|file://somepath...ntu/start/page
to
http://my.yahoo.com in your firefox preferences

have you tried to manually download the packages and install them?