Q: beeping sound when restarting macbook pro

I Have "15 inch Late 2011" Model Macbook Pro,its working normal bt when i restarting my macbook its beeping 3 times and 2 second delay again the same beeping comes and some times my mac book restarts unexpectedly.some days before i seen that "15 inch Late 2011" model have some manufacturing defects and apple solve this free of cost (in this link https://www.apple.com/support/macbookpro-videoissues/ ) after i shown this at a APPLE SERVICE CENTER they run some diagnostic test and told me that "its not a graphic issue we can't Help you". i think they are cheating me because my laptop having same complaints that apple says.  What should i do? anybody can help me Please...