Chosen Solution
Apple MacBook Air “Core i5” 1.7 13" (Mid-2011) My system is not booting up, I get 3 beeps, period, 3 beeps … and it won’t turn on. Please help
The 3 beeps suggest a RAM issue and this model has the RAM chip soldered on the motherboard. Try a PRAM reset to see if it goes away, if not only thing to do is replace the motherboard :( Edit: Here you have a guide to replace the motherboard. @paulamulvey