I suggest that you benchmark you computer to make sure that there are no issues with anyone of the primary hardware. I suggest one of the many 3Dmark and Unigine programs, they can be found for free.
Hardware Monitor is also a must. It will allow you to monitor temps and voltage on nearly all peripherals.
CPU-Z and GPU-Z are also good programs to monitor hardware voltages and speeds.
Fan Speed is a program that will allow you to control the speeds of your fans via the motherboard fan headers.
If you plan to OC, you will need Prime95 to test the stability of your OC. It also helps to detect RAM errors on occasion.
Memtest is probably the preferred tool for detecting RAM errors though.
Naturally, you are going to need an AV program. There are plenty of free programs like Avast and Malwarebyts