Sound problems - how to reset drivers?

I have this Hp dv7 laptop running windows 8.1

when installing the OS ( win 8) some time ago I had no problems installing the drivers for the laptop sound speakers (IDT), though the drivers where meant for windows 7 - the install went flawless and sound was fine.

Then i upgraded to windows 8.1 and still everything was perfect concerning sound.

I know there is no problem with the speakers or the laptop because I dual boot and in the win 7 partition the sound is perfect with the same drivers.

The problem :
sound suddenly stopped. I uninstalled the drivers and tried to install them again but the computer gives this message that they are not compatible. After I uninstalled I was hoping that windows should load or install the generic drivers but that does not happen, there must be something corrupt that does not permit the total uninstall of the IDT drivers and maybe that is the reason the generic drivers wont start installing.

Is there a way for me to install the windows generic drivers? Or maybe completely unsinstall the other drivers from idt sound drivers and software so that I could install generic windows sound drivers?

The problem certainly is related to the DFX software that I installed some time ago. I have uninstalled it to but the problem persists.

Sorry for the long post and if it is a little confusing

I would appreciate very much if someone culd help me...

best regards...