After 2 years, my DP 4 decides not to open anymore. It gives me a "this program has suddenly quit" window during the loading of the Waves plug in. Maybe I should unistall Waves. I have unplugged, rebooted, nothing like that works.

Yes definately uninstall waves. I had that error message too. Sometimes, it works itself out when you are able to get the next update. Perhaps the update that came before DP 4.5( this is the one that I use.) If you go down to the update 4.11 you will need to uninstall D.P. and re-install that version.