If you triple-click on a word then the entire paragraph is selected. I thought that is how it has always been.

The flashing screen is another issue. Never seen that. Maybe try updating graphics drivers?

You can also try disabling hardware acceleration? This can only be done via Excel (not Word) but it applies to Word as well. Open Excel and go to File/Options/Advanced/Display where you can tick a box to disable it. This tip came from Charles Kenyon on this forum.