Audio drivers downloaded but speaker says no device

Hi,

I have a lenovo G575 and cleaned it up today (full scan Malwarebytes, removed bad programs or not using, defraged, emptied trash, updated windows, restart. Everything worked beautiful! Just one problem - no sound. Went to manufacture and downloaded correct drivers for audio and laptop said it was a success. went to speaker by clock said no audio service, went to device manager and went to activate but it said no device....help please,

thanks