Recently I have noticed when I select cells and hit the delete button,
Excel takes a long time to process and locks up for a time. I noticed
it first in macros that select all cells in a workbook and delete. I
recently had a workbook that had gotten large despite having mainly
"blank" cells. I deleted the cells and it froze for 30 seconds or so.
Any ideas of what could cause this? Also any suggestions on the best
way to delete unwanted cells?

I am using:
Excel 2003
WindowsXP Profesional


Thanks - Michael