Black screen?
Why is my screen going black with only the mouse appearing for 1-2 minute periods, and i do no have screen saver
MacBook Air, OS X Yosemite (10.10.3)
Go step by step and test.
Reset PRAM. http://support.apple.com/kb/PH18761
Reset SMC. http://support.apple.com/kb/HT3964
Choose the method for:
"Resetting SMC on portables with a battery you should not remove on your own".
Start up in Safe Mode. http://support.apple.com/kb/PH18760
Repair Disk. http://support.apple.com/kb/PH5836
Best.