No way in a normal procedure ! If u set as read only when u provide password at the time of saving the file, then u may open the file as just read only mode. Else U have to download a 3rd party SW to recover ur password. The link that provides free SW: http://www.freewordexcelpassword.com/index.php?id=download
u have to need .net framework for this.
OR u may also use Password.xla to recover ur file.