I was using google. Suddenly sheer black "curtain" came down screen. Text box told me to shut down computer and start again. Cursor was frozen. Esc button didn't do anything. So I shut down and restarted Then same thing happened again after it booted up.
MacBook Pro
Kernal panic. Often caused by Defective or incompatible RAM.
http://support.apple.com/kb/ts3742
http://www.macworld.com/article/2027201/how-to-troubleshoot-a-kernel-panic.html
This definitely isn't a virus. (I noticed you used the word "virus" in the tags.)
As Leroy indicates, this is called a kernel panic. There are three possible causes for kernel panics: bad hardware, bad third-party software and a badly corrupt system.
First, open the Terminal application (search for it if you can't find it) and paste the following command into the window:
kextstat | grep -v com.apple
After pasting it in, press return. Copy the results and paste them into a new message here. Here's what mine shows:
Last login: Tue Nov 26 05:40:20 on ttys000 Hyperion:~ thomas$ kextstat | grep -v com.apple Index Refs Address Size Wired Name (Version) <Linked Against> Hyperion:~ thomas$
If yours looks pretty much the same, you don't have any third-party kernel extensions installed, which means that third-party software is not a possibility.
If you can't boot in the usual way, try a safe boot.
During startup, you’ll see a progress bar, and then the login screen, which appears even if you normally log in automatically. You must know your login password in order to log in. If you’ve forgotten the password, you will need to reset it before you begin. If you have more than one user account, you must be logged in as an administrator to carry out these instructions.
Safe mode is slower than normal, and some things won’t work at all.
Note: If FileVault is enabled on some models, or if a firmware password is set, or if the startup volume is on a software RAID, you can’t boot in safe mode.
If you're able to boot, launch the Console application in any of the following ways:
☞ Enter the first few letters of its name into a Spotlight search. Select it in the results (it should be at the top.)
☞ In the Finder, select Go ▹ Utilities from the menu bar, or press the key combination shift-command-U. The application is in the folder that opens.
☞ Open LaunchPad. Click Utilities, then Console in the icon grid.
Select the most recent panic report (with a name that begins with "Kernel" and ends in ".panic") under the heading System Diagnostic Reports on the left. If you don't see that heading, select
View ▹ Show Log List
from the menu bar. Post the entire contents of the report — the text, please, not a screenshot. In the interest of privacy, I suggest you edit out the “Anonymous UUID,” a long string of letters, numbers, and dashes in the header and body of the report, if it’s present (it may not be.) Please don't post any other kind of diagnostic report, such as a hang report.
Gray curtain came down on screen. Now computer is frozen
