Audio Problem - Please Help!

I've just bough an Acer Aspire One, and to start with it worked fine, but within a few hours it developed a sound problem. The sound is actually working, but it's suddenly very quiet, like the volume has been turned down. I've checked the volume control, it's on full, and I've tried pressing FN+F8 and FN+volume up/down but to no avail. It's the same with headphones in. It's almost like the maximum volume has suddenly been limited.

Any advice would be appreciated, it's a fantastic little machine and this problem is destroying my enjoyment!

 

In a terminal run: alsamixer
and see whether you can increase the volume there.

Cheers.