How do I un-protect a file?

I would like to un-protect a specific file in a Program Files (x86) subfolder, which the system will not allow me to change without requiring administrative approval (UAC). Is this possible? The file is C:\Program Files (x86)\Mozilla Firefox\defaults\pref\Firefox.js, and I need the system login script to be able to check and modify this file regardless of who is logged in. Is this possible? (I come from an XP background where there was no obstacle to doing such a thing, and I never used Vista, which may behave like this as well.) TIA - JR

ps I'm using Win7RC.

pps I know I could accomplish this by turning off UAC, but I'd rather leave it on if possible--that seems a rather extreme solution to the problem!

This website is not affiliated, owned, or endorsed by Microsoft Corporation. It is a member of the Microsoft Partner Program.