I have a D255E that i buy at the end of may (rev. 13463) so it must be very similar to your; I have PCLOS/KDE, use french canadian keyboard layout. I use it almost daily and, it work great!
At installation time, PCLOS detect a type 105-key (intl) pc keyboard. All i have to do is to specify our local layout in the control center.
Are you sure the internal speaker is not working? If i remember correctly, the mixer don't show it by default at installation time. Anyway, don't spend time activate that crappy speaker as i do, use headphones instead.
For your root PW, write it on a text file on another computer, transfert it on a USB key, open the file on the netbook, CTRL-C CTRL-V, voilà.