anyone having that kind of problem: After switching back from text console mode (Ctrl-ALT-F1; -F2,...) the X screen went black leaving only the mouse cursor visible. At last I found the cure: Many web pages recommend to use the following within /etc/X11/xorg.conf:
CODE
Option "AllowGLXWithComposite" "True"
For my Geforce 7600GS this is the very option to toggle that nasty behaviour. (BTW, does it do any good? I couldn't find any difference - except when I turn it off, I can switch normally...)
HTH,
scholle