Interface TFT LCD with PC
That display is designed to be connected to a Raspberry PI (rPI) board. There are going to be ready made drivers/software programs for the rPI that will operate the display. 

Your next step is to investigate the multiple ways that folks connect a rPI to a PC. Pick one that meets your needs and is compatible with your old PC. Once again there is going to be a lot of open source material to support the software interfacing between the PC and the rPI.

Lastly you may have to devise some software that you write for the PC to pick what information that you want to display and port it out of the PC. You will likely also need to write some additional software for the Linux environment of the rPI to take the PC sourced data and format it for the display. Some or all of this software may already exist as open source so you may just be having to modify it to your needs. 

In the end if you have some electronics hardware skills and a good amount of software skills this is an achievable project. If not then be prepared for a fantastic learning experience and expenditure of a good amount of time.