Do you normally open Windows Mail as soon as you've started up the computer?
If so, is it possible that it's not actually WM that's taking a long time to open, but that your boot up is taking much longer than previously?
I'm wondering whether Pinnacle Studio might have put something into your startup folder that is causing a major slowdown.
You could try running msconfig, then click the startup tab. Check down the list to see if you can recognise anything to do with PS and untick it. Then restart the computer and see whether the problem disappears.
If not, then you can go back and re-tick the unticked items.