Hey,

I started a galactical conquest, the destroyal of Alderaan. But everytime the Death Star is about to destroy Alderaan the game freezes (music is still playing) and I have to kill the game with the task manager. It doesn't matter if I do it while I fight against Ackbar's fleet or try it to do in the galaxy map. Did someone else experienced this?

hmmm....never really heard of this problem.
And your description is a bit vague.....
Loading screen, battle screen?
But one thing you could try (if you haven't already ;) ), did you try to start the game in a different language version?

Easiest way, make a bat-file, with the following line:
swfoc LANGUAGE=ENGLISH

In case you use English, replace with GERMAN

This will start SWOC in this specified language and can be changed any time ;)

Battlewise it freezes after the death star laser fires the laser and the cinematic sequence gets back to the normla battle view. In the galaxy screen it freezes when I pull the death star into the action slot and release the unit.

ok, never heard this one.

You could try to get the xml files from moddb (IIRC) and try again. The GOG version has the MP-fix, which means that the single xml files aren't there.

Maybe this will help your problem as well. Although, as said before, never heard of this problem prior.

Especially the action-slot freeze.

One thing which might be there, a save game corruption. Only way to verify would be starting a new GC. If the savegamedefreezer would help in your case, not sure (if you want to check, search on moddb, yes sorry to lazy to search for it ;) )