Hi,
I am also looking the solution!

I have tried the following:
- I disable hardware acceleration in the PowerPoint
- Set back Security settings
- I know the toolbox insert Flash Object option also, but dosent work

The PC are Win7 and W8.1 with O2013 Std an Pro also.

What I have discover today, that I open an ppt, which was created about a month ago and the inserted swf works fine. When I insert a new slide with swf, the new swf didint start it.

Any idea?