I'm not sure I can help on this, and if not and no-one else in this forum can, try CNET's Microsoft Office forum here;
However, to start with......... I haven't heard of this "Select Sum Field" command or option, so when I accessed Excel's Help, I was offered Pivot Table options. Is this something you have been using recently?
Even if it is, I am unsure how you would "unselect" Pivot Table to return the cursor control to you. This sounds like Excel has become corrupt. You could try the "Detect and Repair" option in the Help menu command, but have your Microsoft Office CD ready as it may ask for it.
if that doesn't help, you could try removing Excel from the Control Panel > Add/Remove programs option, but again you would need the Office CD. You could remove Excel, then take the disk out, reboot the computer, then once Windows has loaded again, insert the CD again and re-install Excel.
Your Excel spreadsheets would not be removed or deleted, as long as they are saved away from the Microsoft Office Program Files folder.
That's all I can suggest at this stage.
When I accessed my Excel 2003 program this morning the data worksheet was locked into the "select sum fields" command. Whenever I moved the cursor in the worksheet it would highlight some of the fields and locks up the computer. I've tried almost everything I know to get out of this command but to no avail. When I open other excel worksheets the "select sum fields" command is there so I'm unable to perform any work using Excel.
How do I deselect the "select sum fields" sommand so I can unlock my computer to work on the Excel worksheets?
Thank you for your help.