Excel 2007 File corruption
 

When copying between two Excel 2007 instances, The program quits copying off
the clipboard, then I you restart Excel, it tells you the file is corrupted,
asks if you want to recover then strips all formatting and tells you data was
lost.

Has happened 3 times in last week.

Running on new Dell mobile workstation with VISTA Professional; Dual-Core
with 4GB memory.

What's up?