Transform PC into Router?

The wireless router's signal in my home is unable to reach the third floor of the house, which is incredibly frustrating. There is no option to move it to a more centralized location nor have the service provider technicians been able to provide any assistance in resolving the issue. I have recently become aware that there may be a way to turn my PC into a wireless router, which, when located on the second floor, would then boost the signal so that wireless devices could operate on the top floor without interruption.

Any comments, advice, and/or suggestions would be most appreciated in resolving this matter. Thank you.