Question...I'm relatively new to Mac. I own a 2015 mBP 15", 256 SSD with 16gb ram. The computer turns on, but it only turns on if I hold the power button for a while. Sometimes it'll take 5-7 seconds before I hear the chime. Is this normal? Also, it's not uncommon for me to get the no proceed sign (like the no smoking sign but without the smoke) and after 5-10 seconds it goes away and switches to the Apple logo before booting. Is this normal behaviour?