[EDIT] the problem is solved, now.
If you use Firefox on Windows, you are probably affected by a Windows bug. There is nothing lichess can do about it, but you can try some workarounds.
Symptoms: Huge memory consumption, and after some time sounds stop working.
How to fix:
- Use another OS or browser. If you're stuck on Windows, try Chrome, it's free: http://www.google.com/chrome/
- Disable Windows sound enhancements:
Control Panel -> Hardware and Sound -> Sound. Double click on Speakers, go to the Sound Blaster tab and check Disable Enhancements. Or with pictures:http://technicallyeasy.net/2010/09/how-to-disable-audio-enhancements-windows-7/
Then restart firefox.
- Try this Windows hotfix: http://support.microsoft.com/kb/981013
. Let us know if it works for you!
Finally, if you're stuck with no sound at all on your computer, try restarting the Audiosrv service.