All an driver is gonna do is listen to the sound cards output of 1s and 0s and put it into an audible form, they just have to be compatible with the sound card. I'm not too sure what you mean by saying not everyone has realteks audio. Do you mean not everyone has the driver or the sound card? i assume you mean the sound card, Because the driver is 'universal for sound cards' i would expect this to work.
Indeed Rocky would want to try the method already stated by you, by going to the website of the sound card manufacturer and downloading and re-installing the correct drivers. If this was not to work for unknown reasons (which has happened to me on more than one occoasion) then i would suggest not going down the path of a new card and hence new drivers and simply use realtek as your 'backup plan'.
Quite simply, there could be a number of reasons that the sound isn't working eg; system software updates, software malfunction, software clashing, hardware problems or simply the guys in the shop have run system repairs with something that doesn't revert settings, or blah blah blah. But most commonly, the audio drivers fail in a PC especially an older model.
