Right I seem to have lost my sound, but only online!!!
I've re-installed flash player since most online sound is played through that on my machine...I'd investigate it a bit further myself but I've just come back from day 6 of an 8 day work marathon (w00t lucky me!) and I've just had the most rubbish day ever so far so if anyone's ever had this before or has any ideas they're more than welcome...
Cheers
Edit: I'm using WinXP SP2 btw, and if you've been around the tech forums before you'll know my compy specs I'm sure, I've got onboard audio with a Realtek AC 97 controller or something...