You can change the default format for all comments in Excel. However, it has
to be done from outside of Excel. Be aware that to change the default format
for Excel comments, you will also be changing the default format for all tool
tips (those little notes that popup every time you pause the cursor over a
tool button) in Windows.
Here's what you need to do:
1. Go to your Windows Desktop (Windows key + M).
2. Right click on the desktop and choose Properties from the popup menu.
3. Click the Appearance tab.
4. From the Item dropdown list, select ToolTip.
5. You can now choose a new background color, font face, font color, font
size, bold, or italics.
6. Click OK to accept the changes.
Note that these changes will apply to across all Windows' ToolTips as well
as Excel's comments.
Thanks to Tim Owens for the tip suggestion.
Note: I am unable to change the default FONT...