No sound on my Lenovo laptop

[khaepmu]

No sound on my laptop. It is driving me crazy. I had it repaired yesterday because I couldn't connect to my wi-fi but my cell phone could. The repair shop saved all my data, downloads etc and then downloaded new windows I think.  When I got home the wi-fi connection is excellent but absolutely no sound for any of my audio downloads or you tube. Actually, I got sound last night after I made I fooled around and made VLC media player my default player. I don't know what I did but the sound worked on everything but this morning after I turned on my laptop absolutely no sound for anything. I have checked the obvious tool bar sound and it is not mute. I have no idea how I got the sound to work last night and can't understand why it stopped working after I turned off my computer last night. Obviously I am a complete novice with any computer tech stuff. Thanks. 

[brokenbone]

i also had issues, there is a link on google that explains it,

just type in along the lines of "no sound on laptop win X"