Hi everyone. I'm new to the forum. Despite over 2 hours trying to find an answer I've only just found you! I'm a mouse man and not clever. I can never remember those keyboard shortcuts so you can tell I'm an amatuer! I've been creating short videos for years and burning some on MPeg2 format. Suddenly, two days ago, I find the computer sluggish and that neither WMP11 or Nero will play back an MPeg 2 file that played happily the day before! The sound is distorted and the playback is slow on Nero. WMP11 plays - but without sound. I've run checks with Microsoft, Kaspersky and now AVG and nothing has been found. Something suddenly caused the problem but I'm at a loss. How can I try different codecs in WMP11. It shows the codecs as Audio Pinnacle AC3 decoder and Nero video decoder. I can't see how I change these?