Access 2007 "compact and repair" asking password

Hi all,

I have a database in Access 2007 format, with a password. Usually after I
open and modify the database, I do "compact and repair" to reduce database
size without any problem. But last time when I did compacting, database asked
me for password. Even though I input correct password, it showed "not a valid
password" and won't compact database.

More strangely, when I open database exclusively to remove password, it
shows "Encrypt with Password" which should be "Decrypt Database" under
"Database Tools" tab. So I can't remove or change the password.

I don't know what is wrong here. It is appreciated if anyone could help!

Thanks!!!

wand