Two more comments. I had forgotten about Trend Micro. That program caused slow down and other issues for me at a client about 5 years ago.
Now maybe it better now, but perhaps a different anti-virus is in order.

Also, in Outlook you have a choice of e-mail editor. If you choose Word, then it's runs in the background whenever Outlook is running. Outlook is a known resource hog, but with a gig of RAM you should have no problem.

Steve