It is most likely frontpage is causing the issue.
You would need to restart your computer and NOT open the file in frontpage until you access if via navigating to the file.
Navigate to the file manually.. ie through your folders where it is located.
You then need to right click on the folder and make sure read only is not ticked.
You mentioned something about my computer and folder options so i'm not sure your doing it correctly.
If your still having issues with your computer stating the file is being used you could use:
http://download.cnet.com/Unlocker/3000-2248_4-10493998.html
However, do this at your own risk. I have never had a problem using this software but thats not to say it can;t happen.
Basically when a file is locked after you install this program you can right click on it and then click on unlocker.
However, I suggest you try and change permissions on you computer first manually as suggested initially.