just to let you know that I have exactly the same problem, ie, the splash screen hangs for ages at somewhere between 40-80%, after which I'm faced with a blank blue screen and a mouse pointer.
These are the things I have tried to date:
1. deleting /home/username/.kde
2. creating a new test user
3. upgrading from mandrake 10 community to mandrake 10 official.
these things have not worked.
After reading the replies that you received, I tried logging on as root and that is fine, except, of course that everything is red and I don't want to be logged on as root..
If you, or anyone else out there, finds a solution, please let me know because I would much rather use kde than gnome