excel format menu will not appear
 

when i'm in certain cells, the right click format key will not activate the
format menu, nor will the tool bar at top format command reveal the format
menu.
I've tried copying a "good cell" into the "problem cell" to overwrite the
unresponsive condition, but does not correct.
I've also tried deleting contents and re-entering. also tried deleting the
row altogether.
this is a spreadsheet with a date column, description column, formula
column, text column, value column, text column, value column (the formula
column refers to the value columns).