Ok, your on your way.
Here's whats happening.
ctrl-alt-backspace restarts your X server(windows).
The fact that you can log on is good. To start your xserver you do two things.
1) init 5
2) startx
Now, by typing startx will try and fire up your xserver, but if its not configured properly you will get some sort of error.
Now, the init 5 is similar to startx but it referes to your run level.
for ex. init 1 = single user mode
init 3 = is what you see now, just a black dos like screen.
init 5 = means at boot up your server will boot into kde(Xwindows) right away.
Now which to choose: startx or init 5?
In your case its best to use startx. Because when your having troubles configuring X, at run level 3 its easier to trouble shoot.
Now to configure X:
Type startx
(note its best to do this as root, therefore log in as root(root=administrator in windows))
If kde starts?, life is good.
If KDE does not start, then do the following:
type: Xconfigurator
This will allow you to configure X. A number of things can cause problems with X setup.
If your monitor or video card, or even mouse is not configure properly your X will not start.
So, sounds like you have been through this before, so go through the steps again, configure your monitor, video, test. If your screen remains black, then start over. You may have to try changing resolution,video ram,different types of monitors..etc to get it right.
If you still cannot get configured, try looking at you mouse settings.
There is a few utilities you can use. I don't use mandrake very much(I'm a redhat person), but most distro's have similar utilities.
Like:
setup
linuxconf
mouseconf or mouseconfig...
You'll have to see whats available to you. Just try typing the above in, see what happens.
Long story short, until you run Xconfigurator, and you see that popup window that says "DO you see this, click OK" X will not work.
hope this helps
jerry