There are many reasons why a PC " behaves" this way.
These annoying " gliches" may be caused by an overloaded hard drive, overworked CPU, Malware, running 2 AV 's, unnecessary data, Browser addons or you may have unnecessary programs running in the background etc....
Troubleshooting steps for you to try -
* Go to search, type device manager and look for any yellow warning markers
* Download SuperAntiSpyware or Malwarebytes, run a full scan after you update
* Run another Antivirus scan.
*Type event viewer, in search (by start button) > Windows Logs > Application & System.
Look for RED critical errors that say app hang, app crash, or anything that relates to the problem.
Note the event ID, and the source codes and Google search them.
* Make sure that you are not over heating.
* Make sure PSU is working properly.
* If overclocking, restore to original.
* Try in safe mode; report back if it works properly.