Thanks very much for your feedback, Tara. I haven't settled on a theme yet or plugins - I only got to play around in the DB and tour the program a little. After I posted this help request, I researched further, and evidently this issue has occurred before in WP after installation/updating functions - at least from what I Googled. I'm trying to research so I can fix it myself, but I'm not sure -- it appears this error can occur for multiple reasons?
Can I still have a plugin or theme issue even though I deleted everything from 3.5.1 from both places (meaning host and my computer files) and uploaded via FileZilla the new, complete 3.5.2 version?
Could the problem be that since I was in the dashboard and WP program yesterday, even though I didn't save any work per se, that the templates and plugins I looked at (with the default Twenty Twelve being one of them) as I was "touring" WP with guidelines in hand, could have caused this problem? Maybe that old info is not yet cleared out?
Should I first compare each file size with what's on my computer vs. what is uploaded to my host? I think the total # of bytes is about 12,070 (have to verify the last 3 digits)?
Before I deactivate the plugins, I would like to confirm, if possible if my specific issue can be corrected via inserting code within the parentheses as I asked above? I have no problem in admitting I have no idea! LOL
Or possibly, should I again uninstall the whole program on host server and computer and start over. I'm just not sure. I'm trying to research and resolve this, but I don't think I understand enough just yet to discern the problem -- only from what I've read today. In one case, it appeared to a browser-related issue; another a server issue...
Thanks again for your suggestions. Before I move forward with resetting the plugins folder, I'm hopeful additional WP-knowledgeable like yourself, will chime in before I make too many changes.
I sincerely appreciate your suggestions. Because of this problem, it's taking me away from updating the rest of the site (not in WP yet - I'm transitioning) -- that said, the blog portion is critical.