Quick Preview a video file reboots computer

If it works in the Safe Mode, try running this program when booted normally and then copy and paste the output in a reply. The program was created by Etresoft, a frequent contributor.  Please use copy and paste as screen shots can be hard to read. Click “Share Report” button in the toolbar, select “Copy to Clipboard” and then paste into a reply. This will show what is running on your computer. No personal information is shown. If the log won’t post, try posting it in Pastebin and provide a link in a reply        Pastebin

Etrecheck – System Information

Do you have any panic reports from the Mac restarts?

Please post a few of the most recent Panic reports.

Look for the Kernel Panic reports at:

Finder -> Go -> Go to Folder -> /Library/Logs/DiagnosticReports

<http://support.apple.com/kb/ht2546>

<http://support.apple.com/en-us/HT200553>

The panic report should have "panic" in the file name.

You can use the "Additional Text" box when you Reply

I notice you have 3rd party RAM. You might want to run Rember just to see if it picks up any RAM issues

<http://www.kelleycomputing.net/rember/>

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Quit as many apps and background tasks as you can (such as menu bar items) so more RAM is available for testing.  Booting into Safe mode <http://support.apple.com/kb/ht1564> can also free up more RAM for testing, by not loading any 3rd party additions you may have installed.

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Set Loops: [X] Maximum

and run overnight

And speaking of RAM, it is best to add RAM is equal sized pairs so that the Mac can use interleaved access to get an extra 10% to 15% performance improvement.

You are welcome. Good troubleshooting.

You have adware installed. 

Run EtreCheck again.

In the Sidebar, click the Security button.

 Locate  and remove entries under  Adware and Unsigned files.

 Click the “Remove” button.

Try downloading this program which was written by Thomas R, a long time poster. The program will search for malware/adware The program will do the work for you which makes it easy. It may be necessary to run more than one scan. After running the scans, restart the computer.

Malwarebytes Anti-Malware for Mac      10.10 and later

Malwarebytes uninstall

Most posters recommend not using cleaning programs. They can destroy normal computer operations.

CleanMyMac 2 uninstall

CleanMyMac3 Uninstall

Check for any remaining associated files using these programs.

EasyFind – Spotlight Replacement

Find Any File

I would uninstall Sophos. It tends to interfere with the computer's operation while providing minimal to no benefit unless you work with Windows files. Most long time posters recommend not using antivirus software or cleaning software such as CleanMyMac.

Sophos Un-install

com.nvidia.CUDA 1.1.0

Try uninstalling the above using the Developer's uninstall instructions.