Weird sound problem.

Hi. When I installed a fresh copy of windows XP sp2 on my pc, I noticed a weird sound defect which really annoys me. The sound has kind of an echo and seems a lot "3D" and because of that I can't fully enjoy listening to music and watching movies with this strange sound. I have C-Media AC97 which I installed from the driver CD that came with my PC. Unfortunately, my Windows copy is not genuine so I can't do windows update, but I tried uninstalling, installing, rolling back, configuring settings, etc. Nothing helps. I have also an icon on my taskbar called Xear 3D which is supposed to control my "3D" sound, but no matter what I change in the settings, the weird echo effect is always present. I tried changing system settings too, but that didn't help either. If only there was a way to reset the settings or something similar to that, I bet it would help, but I'm completely out of ideas. Please help. Thanks in advance. Bazzeh