Quote - OK, having a little bit of a problem. Reality 2 isn't opening up at all. It always used to open up instantly but now nothing, even after 10 minutes of waiting.

Any ideas?

First thought is to go to Help-->About Installed Plugins and make sure Reality has the little green plug next to it.  Double check your Reality version vs the Daz Version. I think you need Reality 2.5 for Daz 4.5, Reality 2 for Daz 4.