Can't do anything with Impress

I haven’t used Impress before, but having just installed the 6.4.1 update curiosity got the better of me and I tried loading an old pps file. I started Impress and used the file open tool bar button, the selected slide show loads but then auto-runs and, on completion exits not just Impress but the whole LO application! I don’t want it to auto-run, I want to edit it, but I can’t stop it running. I double checked with PowerPoint on a different machine in case there was something wrong with the pps, but there it just sat quietly awaiting my bidding and didn’t auto-run, just what I wanted.

So three things I don’t want, autorun on load, exit Impress on completion, exit LO on completion. But I can’t see how to do it, especially as I have to do absolutely nothing to get those actions in PowerPoint.

I’m missing something aren’t I?

I’m using Win 7 BTW.