Software to Set & Protect "read only" status of a file?

Is there a software that will enable me to *easily* make a given file "read only" & then password protect that given file so that no one can change its status?

 

Maybe Attribute Changer ?
http://www.petges.lu/

But I used it too long ago to know if it could be password protected.

 

Easy File Locker

http://www.softpedia.com/get/Security/Lockdown/Easy-File-Locker.shtml

 

It provides no means of protection. Thanks anyway.
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Thanks for the suggestion.

Norton AV killed the EasyFileLocker (EFL) download based on "medium risk" rating by "thousands of users." I had to list the file in Norton's exceptions before I was able to download this. After I finally got EFL downloaded/accepted, I scanned with several different scanners. They all gave it a clean bill of health.

I'll give EFL a try in shadow mode in a day or so. Stay tuned.
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I had some free time so I trialed EFL in shadow mode this PM. I first tried EFL on a "regular" file (startdelay_v3.0b309.exe). EFL processed that file just fine. HOWEVER, when I tried EFL on a file from the specific category of files whose attributes I want to control/protect, EFL refused to deal with them. Ratz!