In many cases, rebooting/restarting your PC, Mac, Phone, or Tablet fixes many problems.
The reason is that your computer is a complicated piece of technology, comprised of many parts from the actual hardware, to the drivers, to different software written by thousands of different people.
When a computer is asked to do something, instructions are sent to your RAM (Random Access Memory), over time instructions are written and erased, over and over and over. Sometimes, some of these instructions clash with other instructions and problems occur.
When you reboot/restart your computer, you are erasing this temporary memory storage and starting fresh. If the problem was related to clashing instructions you find your problem is fixed! If the issue persists, then it is another issue.
Clashing instructions happen all the time, and are the cause of many, many issues, hence the reason why we (your tech support people) ask you to reboot as one of the first troubleshooting steps.
So, the next time you experience a weird problem with your computer, reboot first!, you may find you don't even need to call support in the first place!