OK.......
When you have the black login screen, does the caps lock LED on your keyboard change state when you press the caps-lock key? (You know the three lights on the keyboard for num-lock, scroll-lock and caps-lock)
If it changes then your keyboard is working.
Make sure you still use the same Case When You Type In the PassWord (Like, GlennsPref) even though you can't see it.
The prompt should change after you have logged in.
Then you can type startx.
You could try asking here......
http://forum.mandrivaclub.com/viewtopic.php?t=39641&