Here's how you crack the password protected Microsoft Word file: First, open the document and do a "Save As..." specifying Rich Text Format (RTF). It'll end up being called something.rtf.
Now open the RTF file by double-clicking on it. It should look identical to the original Word file.
Final step:
save the RTF file with a new name as a Microsoft Word format document. That's all there is to it.
You've sidestepped the read-only lock on the file your boss sent you and are good to go. In terms of actually breaking the password on a file that has it set as the "open file" password, that's beyond the scope of what I'll write about here.
But I will say that there are some Google searches that can probably help you track down plenty of tips on doing just that.
