These 2 functions no longer work. I did not do anything special from 1 day
to the other and suddenly I could no longer undo or redo. I have uninstalled
and reinstalled Excel 2000, but this did not solve the problem. I can only
think that I installed an MS fix that would have caused this. Any idea
anyone?

You could be using a workbook that has event macros. Most macros that do
anything destroy the undo/redo stack.

I'd start excel in safe mode:
close excel
Windows start button|Run
type:
excel /safe
and do a few things to see if undo/redo work.

If they work ok, then you'll have to find the workbook that contains the macro
that's doing the damage.

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

=======
Another thing that could have gone wrong is that a registry entry was tweaked.

There's a setting in the windows registry that tells excel how many undo levels
to keep track of--maybe it was set to 0.

xl2k and above
XL: How to Modify the Number of Undo Levels
http://support.microsoft.com/?kbid=211922

xl97
XL97: How to Modify the Number of Undo Levels
http://support.microsoft.com/?kbid=162944

Andliz wrote:

These 2 functions no longer work. I did not do anything special from 1 day
to the other and suddenly I could no longer undo or redo. I have uninstalled
and reinstalled Excel 2000, but this did not solve the problem. I can only
think that I installed an MS fix that would have caused this. Any idea
anyone?

--

Dave Peterson