After upgrade to 11.04 i do not have sound

[bsuton]

Hello,
I have made upgrade Ubuntu 10.10 to 11.04 but now i have some problem. I do not have any sound on my computer. On the 10.10 sound was perfect.
If anyone know what can be problem please help me.
Thank you.

[dino99]

i've got this problem too and found that ubuntu-restricted-extras was no more installed, check medibuntu too

[bsuton]

These packages are installed already. Something else is problem.

[bsuton]

I still do not have sound.
Does anyone knows what can be problem?
And how to solve it?
Thanks.