I think it's time for some detective work.

First close excel and reopen it in safe mode:

Windows start button|Run
excel /safe

Then File|Open one of your troublesome documents.

Opening in safe mode means that macros are disabled -- and other struff
(workbooks/addins/toolbars) won't load.

Can you close it normally?

If yes, then it's time to read some more...

Chip Pearson has some notes on how to diagnose startup errors:
http://www.cpearson.com/excel/StartupErrors.htm

And Jan Karel Pieterse has more notes:
http://www.jkp-ads.com/Articles/StartupProblems.asp



Terry Hope wrote:

I have Excel 2002. In the past few weeks, I CANNOT close a workboook, even
if blank, without getting the "save as" dialogue box. If I cancel the
dialogue, it just takes me back to the blank workbook & I start all over
again. The only way I can close without saving is to hit the "X" in the top
right corner. I've checked macros and links and they are blank. What have I
done?

--

Dave Peterson