Catrin and Catriona--THANK YOU! I moved my Mail folder to the D: drive and redirected Tbird to save my emails there, and then deleted the mail on the C: drive and it immediately freed up almost 3GB of space!

I will go through the other steps tomorrow (Friday is my usual Admin and IT day), but today I have to get some items out to clients that I could not do yesterday (MTW are my Projects days), and then move on to Marketing and Research (my usual Thursday focus).

Thank you both so much! I will report back on the other strategies (partition manager, etc.) and how they work tomorrow.