Niki, Rikki is right about the too long of a job attempting to configure your existing Impress installation.
Being to be able to fully render a Powerpoint file including sound is important to me so I have come up with what I posted above with the addition of the following.
I like Mint 8 LXDE which natively renders sound in PPT and was disappointed to find the Mint 9 LXDE did not natively contain Open Office in an attempt to make it even lighter. The Gnome editions all contain OO, as far as I know, and, in interest of this discussion, I just tried Mint 8 Gnome Live CD and it successfully renders sound in PPT. Again, I suggest you try Mint 9 Gnome Live CD.
For me, I have compromised to fully play PPT vs the very latest version of Mint. I am still using my installed Mint 8 LXDE.
You might also try Synaptic Package Manager to install the Powerpoint Viewer
. Be sure to refresh it before entering "powerpoint" in the search window and you should find pptview
that is something like an 80mB install. The install includes Wine since pptview is a version of Microsoft's free Powerpoint Viewer. Since I don't have Mint 10 installed, I don't know if you will have luck with sound, but it may be worth the try.
Also, make sure your version is fully updated. It would be nice if this alone would solve the sound problem
My Powerpoint test file is available here: http://www.box.net/shared/8is4icl0mb