bombe_zwanzig: I tried to play vanilla right now, cause i know it's buggy under win7, but the lines in the fallout .ini which alter the multicore-behaviour have been changed by GOG already. it should run. should. hmpf.  
 edith reminds me: i also changed compatibility to xp sp3 and gave admin rights. 
 Thiev: it happened to me once on my own (not testlab) machine - I had to switch to windowed mode for initial boot and after that it was safe to play in fullscreen.  
 but I couldn't get a reliable repro and my PC has lots of weird stuff floating around, so I just ignored it. 
 nope. tried that just now and still the same. and it does this from wherever i start the game, galaxy, startmenue, just the exe-file. doesn't matter.  
 so to sum up what i tested: 
 xp sp3 compatibility 
 start as admin 
 windowed mode 
 switched off second monitor via settings  
 so far no fallout for me :(