I don't know why, but when i have installed Rainmeter on my dell studio xps 1640, then all the sounds from my laptop are muted and just can solve the problem if i uninstall and reboot the computer ... Can you pls say me why i have this problem?

PS: i have Windows 7 Professional 64-bit, an intel core 2 with 2.3 ghz, an ati graphic card with 1gb graphic memory ...

Thanks

Maybe its a skin you have installed? They can change the volume.