On the control bar, click Search to bring up a search box. At the bottom of that search box is “Advanced Search”. Click that.
On the advanced Search Page, you can search by word/phrase, and narrow it down by the poster that posted it. Simply type in the first few letters of the user’s screen-name, and wait a few seconds and the S/W will make a suggestion about the username.
For example, type in “kel” and wait…….It will suggest Keltin. Click the suggestion to select that user. Then search away.
You can also go to a user’s profile page and select “Statistics” and then select “Find all threads started by XXXX” where XXXX is the username of the profile you are viewing.