I have a computer for last few years and everything was OK. I bought a new bigger hard drive but computer could not recognize it. That is why I had to download a new version of BIOS from the manufacturer site. However, after I installed it, have a problem with my 5.1 Speaker system. One speaker failing, the others are OK and WinAmp sound all distorted.
Your computer is obviously does not recognize your sound card as 5.1 sound card. It thinks that you have a four channel stereo card. That is hearting your DirectX system and that is why your Winamp sound all distorted. The reason for that is probably your BIOS installation. I hope that you follow the complete instructions for updating the BIOS on your motherboard. If you do, first step was to make a backup copy of your old BIOS. In that case, find a procedure how to restore your old BIOS and do that first. If you will have the 5.1 sound after that then you obviously have the wrong version of BIOS update for your motherboard. You will have to find the right version for your motherboard and install that version. You would have to pay attention not only to the type of motherboard, but also to the revision number for your type of motherboard. If none of these advices helps you then you will have to ask for professional help.