In excel, you can setup a file so that you need a password to open it
(Go to File -Save As. Click on Tools - General Options) but this can
be bypassed using tools readily available online.

The only way that I know of is to use a 3rd party encryption software
to encrypt the file for you. If this is your standard confidential
info and not nuclear launch codes, try using WinZip to compress /
encrypt the file. You can use 256 bit encryption and it's rather easy
to encrypt / decrypt your file.

On Jun 2, 7:45 am, Wanna Learn
wrote:
Hello 2 questions - I hid a workbook by using Windows - Hide then I
saved the file . I can unhide the book - Windows - unhide BUT I don't want
the book hidden anymore. how dow I do that? Most of my files have
confidential information. My files are in a network drive and I do not want
someone else to open them. How can I prevent others from opening my files,
copying or altering the files? thanks