Congrats on getting back into PC gaming! If you already purchased this (used?) from an eBay seller then I won't suggest alternatives since it's already on its way to you. I will hope and assume that you paid a fair price for it.
My most important question: What games you are hoping to play?
Here are my observations and suggestions for how to take the best advantage of this rig in 2020:
Let's start with the CPU. The i7-4770 is still a relevant processor. It is 7 years old now, so it won't be able to keep up with the modern flagships, but it was fairly high-end when it was released and it should still give you solid performance in most games.
The GPU will have a tougher time in modern triple-A titles. The GTX 750 was a budget graphics card when it was released 6 years ago, and overall I would say it is the weak link of this system. In graphically intensive games you should expect to target 30fps at a mix of low settings, and potentially a drop in internal resolution to 720p. A GPU upgrade is certainly an option for this rig, but we'll need to know what power supply it has first.
8GB of DDR3 RAM is still suitable for many games, but not all. Luckily an upgrade to 16GB should be cheap and easy to do if you decide you need it.
One thing I would absolutely recommend doing right off the bat is buying an SSD. That will really help keep this system relevant. A clean Windows install on a new SATA SSD is something I would do first thing when you get it, or soon after. That 2TB HDD will be fine for bulk file storage but it will be sluggish in the OS and games.
Let us know how it does when it arrives!