XP OS is corrupted and don't know administrator pw to sign on

My XP is corrupt and I am trying to use a recovery tool
that asks me for an administrator password to be able to
enter and repair the files. the operating system was
preinstalled on my dell.. so I don't think I ever had
created a password.

If i did provide a password, I don't remember what it was
or if I need to follow any guidelines (number of
characters, atleast one number, etc).

Please let me know if there is a way to use a repair disk
to repair my files without havinga password and if there
were any requirements I had to follow if I did give a
password