Vaio fit 15 screen takes time to turn on

[Smungur]

I've had a vaio fit 15 for about 1 and a half years, now when I turn it on, the fan makes loud noises and screen takes a lot of time to turn on. Sometimes 30 minutes, sometimes 2-3 hours! It's very frustrating and has caused me embarrassment many times at work. I really need a solution here please! Thanks in advance