installation password

In fiste escuse me for my english... So when I install my Dapper Ubuntu one a laptop, I set a password like : xb"(dl&à and after when gdm start I can't login. So I installe again Dapper and set a new password who work well. I was thinking it was only a installation probleme but when I change it in gnome, and try again to login the same probleme happend. I sow too, that some time the keybord is not understand well some time I try ctrl + alt + f1 and its not working (not all the time) and when this don't work the number don't work too, just letter kye stil working. I newer have it before on debian. totoroavi