Help please

[Disturbedguy]

So I formatted my PC today, as I have done 100's of times before, but now I seem to be having some strange issues that I have never enounctered.

So here goes, if I play music via Windows Media Player, play CoD4 or getting messages on MSN I get sound, but I dont from sites such as YouTube whether it is music or videos and then I dont from Ventrillo although I did a little earlier?

Can anyone suggest anything?

I have gone through everything I can think of, but still cant find out what the hell is causing this problem and it is really beginning to frustrate me.

[watercooled]

Here's a few things:
Check volume is up on Youtube (sorry for stating the obvious but it is easy to miss)
Make sure flash player is updated
Check Windows volume mixer

[Disturbedguy]

Hmm i restarted and everything sound wise is the norm now..i thought it may have been something caused by the game, so jumped in played for 30 mins then out, but all is fine..maybe it just needed a restart...will update flash now though