I'd use a macro like the one at Debra Dalgleish's site:
http://contextures.com/xlcomments03.html#Resize

If you're new to macros, you may want to read David McRitchie's intro at:
http://www.mvps.org/dmcritchie/excel/getstarted.htm

kcampbell66 wrote:

All of the comments in my worksheet resized themselves. I don't know if I
had a keystroke combination that did this. I have a comment in the first
cell of many rows. I was editing the fist comment and all of the other
comments suddenly became so narrow that I could not read what was in them. I
have no recollection of changing these other comments. Is there a way to do
this?

--

Dave Peterson