If you use a lot of different usernames and passwords it is difficult to remember all of them. KeePass is an interesting solution where all your passwords are kept in one safe place and protected with one password.
If any file can not be deleted, then you can use the program LockHunter, which removes the active connections of other applications to that file, which allow you to change or delete file.
Power Search was a real useful feature and there is now good reason why Apple decided to ditch/hide in iTunes version 11. But luckily you can bring it back quite easily. Check it out.
