If you are buying new, go with current tech.
I5-7400
B250 motherboard
Cooler is included with non K processors so no need for aux cooler or paste
Always buy ram in 2 stick kits so you can run in faster dual channel mode.
If you ever want 16gb, buy your 16gb kit up front; ram is cheap enough.
Ram must be matched, and adding ram later is not guaranteed to work.
Love the ssd. If budget is an issue, defer on the hard drive, it is easy to add one later.
If you do want a hard drive, look to Western digital blue/red/black for better reliability.
Antec HCG 620 is good.
I see a better Seasonic M12II 620 for a very nice price
https://www.newegg.com/Product/Product.aspx?Item=N82E16817151095
I would NOT buy a copy of windows that sells for much under $100. It is not legit and you are asking for trouble .
FWIW---
MY build process:
Before anything, while waiting for your parts to be delivered, download
and read, cover to cover your case and motherboard manual.
Buy a #2 magnetic tip phillips screwdriver.
1. I assemble all the parts outside of the case.
That lets me test them for functuonality easily.
A wood table or cardboard is fine.
2. Plug in only the necessary parts at first. Ram, cpu, cooler, psu.
Do not force anything. Parts fit only one way.
Attach a monitor to the integrated motherboard adapter.
3. If your motherboard does not have a PWR button, momentarily touch the two pwr front panel pins
4. Repeatedly hit F2 or DEL, and that should get you into the bios display.
5. Boot from a cd or usb stick with memtest86+ on it. memtest will exercise your ram and cpu functionality.
6. Install windows.
7. Install the motherboard cd drivers. Particularly the lan drivers so you can access the internet.
Do not select the easy install option, or you will get a bunch of utilities and trialware that you don't want. Drivers only.
7. Connect to the internet and install an antivirus program. Microsoft security essentials is free, easy, and unobtrusive.
8. Install your graphics card and driver.
You will need to remove the graphics card later to install your motherboard in the case.
Make a note of how the graphics card latches into the pcie slot.
9. Update windows to currency.
10. Only now do I take apart what I need to and install it in the case.
11. Now is the time to reinstall your graphics card.