P7 did the crash to the desktop.  Often times when that happens, the ini file gets corrupted.  You need to locate the prefs folder (usually found in Users>app data>roaming.  Make sure P7 is closed.  Delete the ini file from the prefs folder.  it's been recommended to delete the library xml file as well but I usually don't.  The ini file will rebuild when you next launch P7.  It might take an extra minute to load but no biggie.  Load a new blank scene and load some content.  Doesn't matter what.  Save the scene.  Close P7 and then re open in.  Load the scene you just saved.  If everything loads as it should, things should be ok.  I don't know how many times I had to do this with P6 and P7.

P8 could be a Flash problem.  Unless you need an up to date version of Flash for other things, I don't bother to up date it.  Tech support told me way back when P8 was released that the version that loads when you install P8 is one that's optimized for it.  I don't know how true this is but I can tell you that except for the IE 11 issue, Poser 8 runs fine under Windows 7.

What's the newest version of Poser you are running on your systems?  The only other time I've encountered the fading screen issue was when I had a problem with Windows Explorer.  For a while, Windows Explorer would suddenly stop working and I would get the pop up telling me that it had stopped and giving me a couple of choices.  I never did figure out why it was doing it.  I started after one update and then disappeared after another. 

If the problems persist, you might want to uninstall the apps, run a cleaner app like CCleaner to get clean up leftover garbage and then do a clean re-install.