How do i stop the W key/the object selection tool from shutting down my computer

Is it happen in Photoshop only, or in other programs as well?

Does the same thing happen if you click on the Object Selection tool in the Toolbar?

Out of interest, open Edit > Keyboard Shortcuts and remove the W shortcut from Object Selection.  Leave it in place for the other two selection tools, and see if the W key still shuts your computer?

We can see you are using a Windows system.  Is it in good health?  Have you had issues with other apps?

How old is your computer, and what is its specs?  Open Photoshop and go Help > System Info > Copy and paste to this thread.  That will tell us a great deal about what might be causing your issue.

Please read this (in particular the section titled "Supply pertinent information for more timely and effective answers”):

https://community.adobe.com/t5/using-the-community/community-how-to-guide-tips-amp-best-practices/td-p/11601738?page=1

What have you done for all-purpose trouble-shooting so far? 

https://helpx.adobe.com/photoshop/kb/troubleshoot-gpu-graphics-card.html

https://helpx.adobe.com/photoshop/kb/basic-trouble-shooting-steps.html

Unless you provide more info about your system I'm afraid your post doesn't make a lot of sense. The object selection tools uses hardware accelerated functions, so the first thing to do would be to update your graphics driver and check the relevant preference settings in PS. Anything more will require much better info.

Mylenium