a good starting place would be to do nothing to the pc until you do some reading on how to un-install/install audio drivers in a Windows os. Reading instructions on unknown websites may or may not be your solution. It's up to you to detemine if and how the instructions apply to your particular situation and hardware.
There are many sources for this information. First you need to determine what sound card or chipset (if on-board) you're having problems with. Then visit that manufacturer's website for information/manuals/instructions for that particular hardware. They usually have pretty simple instructions posted or included with the driver. However, it does require a bit of effort on your part if you want to get your hardware working.
You have basically given us nothing to work with that will allow us to possible know what Avance sound card/chipset (or motherboard) you have, what driver you have installed, if it's the correct driver, etc?. It also sounds like you have no clue how to uninstall a driver correctly then install the right one. Again I suggest reading, then if you need help, repost with some usable information and details of the problem and hardware involved.