I sort of broke the CQWP on top-level site while trying to customize it via
the many posts on WEB. It seemed very straightforward, but.... In general what
I intended to do was:
1) modify xslt of ItemStyleSheet of top-level site to have CQWP display
available data fields from lists
2) modify the CQWP to pick additional data fields as desired
3) re-modify the ItemStyleSheet to display the additional fields.

Did not get #1 to succeed. CQWP will not display at all, says contact site
administrator(me). I tried deleting the old CQWP and inserting a new one as a
new WP using the GUI. It too will not display at all.

I carefully copied and pasted an existing style using SPD, renamed the new
style, & then added 3-4 lines to display names per WEB examples. I'm guessing
I messed up with the check out, check in, and file saves.

What is the relationship between the check in and file saves? Do they have to
be done in a particular sequence? I think I tried all sequences. If I did mess
up the html lines, what would the error symptons be? I did not try to re-set
the site definition yet.