On SKY Methyl, Desk Top, Wndows XP, Norton, Not for Music, I do not bother with that, It was something on You Tube Regards a car Problem that I could not hear due to no sound.
Do you have a cd/dvd drive on your computer?
If so, have you tried playing a music disc? If this plays OK there's something wrong with the Youtube clip.
Also, if you do have a separate soundcard, you could:
1) shut down the comp and unplug it
2) remove the soundcard
3) plug back in and fully boot up the comp without the soundcard
4) shut it down again/unplug
5) re-mount the soundcard
6) plug back in and re-boot the comp again and see if that does the trick.