Pivot Table in Excel 2010 - Excel cannot complete this task

Hello I have a user that is running a pivot table on a data base.  They tell meThe pivot table is not  processing and an error message continually appears -

Excel cannot complete this task with available resources.  choose less data or close other applications. 

We are using a HP Desktop with 8 Core CPU and 16 GB of RAM, which is more than enough processing power on this unit.

Please can you advise on next steps to resolve.

Thanks

Jenny

Jenny