Asus A8N32 SLI Deluxe Motherboard audio problem

The board has Realtek's AC'97 chip. This has worked fine for about 5 years, but I recenly rebuilt the PC in a new case (my new one got rennovated with newer components). So I went on to play CoD 5 on this board only to notice the left speaker on the onboard sound is extremely distorted on high volumes. I have to have the volume on max because my speakers aren't amplified. The sound used to be fine. What I also noticed was the LINE IN input left channel is completely DEAD only the right channel for line in works. Also when sound recording, the right channel is OK while the left channel is distorted even worse than through the speakers stream. Is this a running problem with realtek's AC'97 chip or is there more to it? All my drivers are up to date.