Unfortunately, I have to agree with the others. As you note, you need a new CPU, GPU, motherboard, and power supply. This also means you'll need new RAM as well. Cases from prebuilts frequently don't have all the parts standardized as well and are a bear to work with, so realistically you'll need a new case as well.
The only part that might be transferrable is the hard drive, but you didn't provide details.
Similarly, you may be able to take Windows 10 to a new build if this was an upgrade from Windows 7/8 rather than Windows 10 included with this built, the former striking me as likelier given the age of this PC.
We're essentially talking about a new PC here. If you have a budget, I'm sure one of us will be able to assist you.