whats default password for connecting to pc ??

hi,
just updated my playbook & thought i'd add some movies onto it from the pc & its asking for the password.
well ive no idea what it could be, ive tried what i think it could be & it failed , ive also tried 0000 which i thought could be the default password but it failed so it looks like it only gives me 5 attempts . so can anyone tell me the default password.
thanks