No prompt when closing worksheet to save/ cancel

Have two users using excel 2000 with latest service packs.
Problem is when closing the worksheet it doesn't prompt to save / cancel etc.
It automatically saves the changes they made.
This happens on the network & on the local drive.

I use this effect but the other way round, it closes the file without saving changes but also without the prompt box too.

Check the 'Workbook_BeforeClose' function to make sure its not coded to automatically save.