Running Windows 7 SP-1 with a RealTek AC97 sound card, some of my customized system sounds have stopped playing. In general, the sound works. However, there are sounds associated with certain system functions which don't work, including select, minimize, maximize, restore down and restore up, open and close program, start and complete navigation. I understand that many people don't want sounds associated with these functions, but I find them helpful. Things which I have tried, and which haven't resolved the issue: restore a saved registry from a time when all sounds worked; verified that the system events are associated with sounds in Control Panel/Sounds, and the sounds are audible when tested; over-wrote Windows/Media sound files with fresh copies; ran SFC /scannow; imported the AppEvents key from the registry of a Windows 7 system in my office which plays all the sounds; installed the latest sound card driver.