Salem

Neither vanilla or BDSaleM clients let me get past the initial splash screen, which disappears after a few seconds leaving blank screen.

The Enders client lets me log in, but both I and any objects seem to be rendered underground - please see attached screenshot. You can see my character and the leaves from a tree in the texture that should show rock face.

Have uninstalled Java, deleted cache files and reinstalled both win32 and 64 bit versions of both Java versions 6 and 7, but still no fix.

Any suggestions?

What graphic card you have?

It might be good idea to visit your graphic card manufaturer site and check for newer drivers.
If you have newest one, try installing ~1y older ones it's weird how many times that helped me with some games(*usually older ones through) xD

look here viewtopic.php?f=10&t=767&p=7403#p7403