I tried the uninstall/reinstall trick, and all went smoothly, except that the no sound problem did not go away.
Regarding the 3 usb connectors on the Dell Studio, they all work with external harddisks and mobile phone transfers, but I had a strange experience with a Pinnacle/Hauppauge PCTV usb nanostick. It also seemed to install correctly, but could not receive signals to the vendors TV recording program. However, I then went into Microsoft Media Center and it readily started the TV station search that the dedicated software could not. That solved the TV problem, provided that I can live with recording only in the .WTV format.
Could there be some general screening out of "non-certified" third party programs by one of the Microsoft installs? As Microsofts media programs offer no MIDI keyboard input I cannot test this for the MIDI problem, or can I?