No sound on laptop

I took my laptop in to be fixed because there was a pretty bad virus on it or something (sorry i aint no computer expert) and when i got it back there was no sound.... When i open itunes it says that "itunes has detected a problem with your audio configuration" and i just dont know what to do and when i trouble shoot the problem everything seems fine.... the volume icon that is suppose to be on the toolbar at the lower right is like not the same and when i click on it it says "audio device supported by this application is not detected help!!!!!!