A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Difficult, if not impossible, to assist without a copy of the VBA code.
However, check the following
If there are any loops in the code then ensure that the code is not is not going into an endless loop.
Ensure not trying to process all cells on the worksheet. While technically this should work, I have seen the "Not Responding" when a user has referenced cells (which is all cells on the worksheet) instead of referencing a much smaller range.