Black screen, some functioning controls

Hey there, everybody; I hope I got the right forum, here!
Anyhow, I’ve been using Blender for a fairly short time, but ever since I installed a new GPU (from an ASUS GeForce 6800 Ultra (256 Mb) to an ASUS GeForce 8600 GT (512 Mb)) and the latest drivers, and now I find myself with somewhat of a predicament:
I’ve included an image below, but to sum things up the actual Blender screen is completely black, although the DOS window displays text (“Checking for installed Python… got it!”). I can also summon up Blender:Render using F12, but it just shows me more blackness. Also, my cursor changes to the scaling arrows whenever I drag it over a place where there should be menu panel edges. No signs that it’s not responding, in other words.
I’ve tried un- and reinstalling Blender, but to no avail. I have a similar issue with Google SketchUp (beige background), but 3D applications such as The Elder Scrolls IV: Oblivions and gmax work just fine.
Also, I’m running Windows Vista (Business edition), if that’s relevant.

Thank you for your time!