Can not figure this out for the life of me.

At work here, there is a folder on the network with some Excel files. Three
people are trying to open up and edit these (One at a time, to my knowledge).

Person 1 and Person 2 can open up and edit all of the files in that network
folder, however, Person 3 can edit 3 out of the 5 files no problem. The other
2 files, if person 3 tries to edit them, gets a pop up box titled "Unlock
Range" "Enter the password to change this cell:" no matter what cell Person 3
tries to edit.

Doesn't matter if Person 3 tries to double click a cell, right click a cell
or try and edit the cell from the formula line, it always pops this box up. I
tried a few passwords and even tried pressing ok when it was blank, but to no
avail.

I even tried copying this file off of the network to my local computer, and
I get the same pop up box.

The file properties outside of Excel are not marked "Read only" or any other
attributes that would limit it.

I have checked everything possible that has to do with this problem
according to Microsoft's help, so I now turn to you guys.

Something interesting, under the Tools menu, then Protection, the option
titled "Allow Users to Edit Ranges..." is grayed out so I am not able to
select it, though this sounds like the exact option that I need. One of the
other options called "Unprotect worksheet" asks me for a password also, which
I have tried a few and leaving it blank too.

I can not get to edit these files except for on a select few employees
computers where I do not get any of these prompts at all!

This is so bizarre! Has anyone else had this problem? And found out a way to
fix it? I have uploaded a picture of some of the options I have already
checked to give you guys a better idea of what I have tried to do already.

The image is located at:
http://www.we-todd-did-racing.com/vi.../1005596_1sevm

Please help! If you guys need any more details, feel free to ask away. I
will try and check in every now and then to see the replies!

Thanks so much (In advance)! I appreciate it!