Beats audio on HP ENVY 4 Notebook PC | no drivers

Hello, i had to make a format for my  HP ENVY 4 Notebook PC, lost most drivers, and trying to get em, now the beats audio drivers cannot be found at all, i don't know how to get em back, my os is Win7.
volume  buttons never show progress on screen, and mute button never show red light when muted, like it used to be. and their is no more beats audio software on my notebook.