any suggestions?

 

Click on the My Profile link on the top of the page. Scroll down about halfway to where it says Private Message, then look to see if the checkbox for " Pop-up notification of new Private Message?" is checked or not.

 

Its hit and miss with some people. I get pop ups most of the time. Sometimes if you open a window but it doesnt load all the way the system will mark the PM as notified even though the popup didnt occur. Its just a timing issue more or less