Excel 97: Shared workbook opens only Re

We run a Win 98 peer-to-peer network in our office. Several Excel 97 workbooks with write access are shared amoung the office with no problems. However, one PC (call it PC-A) cannot write to some workbooks of one (and only one)other PC (call it PC-B). PC-A can write to the workbooks of other PC’s in the the office, and other PC’s can write to the workbooks of PC-B, including the workbook that PC-A cannot write to. The workbooks in question always open up in read-only mode for PC-A. The worbooks are password protected, and the password prompt does not come up for PC-A as it does for the other PC’s, which may be the root of the problem.

What is causing this problem and how do I solve it?

Thanks.