Please restart in Safe Mode (by holding down the Shift key) on start up and let us know if it works. This should tell us if it is a software issue, which I believe it to be. That failing, start up holding down the R key, next try the option key and see if you can choice the repair partition. I suspect either virus or corrupt GPU drivers. What OS X are you running?
'''UPDATE'''
Try staring in Recovery Mode, run Disk Utilities.
To enter this mode at any time, do the following: 1) In the Apple menu, choose Restart or power on your Mac. 2) As the computer restarts, hold down the Command (⌘) – Option (⌥) – R combination immediately upon hearing the startup chime. Hold the keys until the animated globe appears on the screen.
This may also be a virus.
If you can save your user folder to an external. Then, In recovery mode do a reinstall of the system.
Please restart in Safe Mode (by holding down the Shift key) on start up and let us know if it works. This should tell us if it is a software issue, which I believe it to be. That failing, start up holding down the R key, next try the option key and see if you can choice the repair partition. I suspect either virus or corrupt GPU drivers. What OS X are you running?
+
'''UPDATE'''
+
Try staring in Recovery Mode, run Disk Utilities.
+
To enter this mode at any time, do the following: 1) In the Apple menu, choose Restart or power on your Mac. 2) As the computer restarts, hold down the Command (⌘) – Option (⌥) – R combination immediately upon hearing the startup chime. Hold the keys until the animated globe appears on the screen.
+
This may also be a virus.
+
If you can save your user folder to an external. Then, In recovery mode do a reinstall of the system.
Please restart in Safe Mode (by holding down the Shift key) on start up and let us know if it works. This should tell us if it is a software issue, which I believe it to be. That failing, start up holding down the R key, next try the option key and see if you can choice the repair partition. I suspect either virus or corrupt GPU drivers. What OS X are you running?
+
'''UPDATE'''
+
Try staring in Recovery Mode, run Disk Utilities.
+
To enter this mode at any time, do the following: 1) In the Apple menu, choose Restart or power on your Mac. 2) As the computer restarts, hold down the Command (⌘) – Option (⌥) – R combination immediately upon hearing the startup chime. Hold the keys until the animated globe appears on the screen.
+
This may also be a virus.
+
If you can save your user folder to an external. Then, In recovery mode do a reinstall of the system.
Please restart in Safe Mode (by holding down the Shift key) on start up and let us know if it works. This should tell us if it is a software issue, which I believe it to be. That failing, start up holding down the R key, next try the option key and see if you can choice the repair partition. I suspect either virus or corrupt GPU drivers. What OS X are you running?