The fans are loud please help?

I have a mid 2011 macbook pro and when I open two aplications on it the fans roar with loudness and its just anoying and then it becomes very laggy.

RIght now as im trying this I only have safari open and I can still hear the fans slightly.

I have it plugged in, and I got the application Memory Clean and it says I had about 1.5 to 2.0 gigs FREE. So I dont know whats going on. We have had it taken in before for this and they fixed it but idk if this just happend or if I need to take it in again.