This is XP Sp2, C2D 6400, 2 GB RAM, Asus MoBo with RealTek audio device.
After installing the software (actually a bunch of it, including Switch, WavePad, ExpressBurn, ExpressRip, but I believe it's SoundTap that causes the trouble), the Realtek sound device is dead. Checking 'Sounds and Audio Devices' in the control panel, I get 'no audio device', all buttons and boxes there are greyed out. DVD-Writer, DVD-ROM and WebCam not recognized anymore.
I uninstalled those in Device Manager, then running the Add Harware wizard brought them back to life but not Realtek. Uninstalled all NCH software and cleaned the registry, to no avail, the sound device is still dead. Device is enabled, driver info says it's working properly, properties are set to 'use audio features ... use mixer features etc on this device'.
Any hint much appreciated.