Trying to install windows 7, keyboard and mouse stop working

What is the processor??  Intel i...........

You have an eighth generation Intel processor.  That is the problem.  The chipset that comes with that processor has no USB 2 drivers.  Win7 install has no USB 3 drivers.  That is the problem.  

The fact that your processor is 6th gen or later is why I asked.

You need to create a Win7 ISO with integrated USB3 drivers.  The problem you are experiencing has nothing to do with your keyboard or mouse.  It is with the ports they are plugged into.

Dell has a web page that describes how to do this.  It is quite technical.  A key tip: you can copy those long command strings using the clipboard feature and paste them into the command window.

https://www.dell.com/support/article/ca/en/cabsdt1/how11804/how-to-install-windows-7-on-systems-with-skylake-chipset?lang=en  This page refers to Skylake processors which is the 6th gen, but that's alright, same problem, same solution.

I have done this myself.  It works.   Once you have created that USB ISO, save it.  It is valuable.  It has been several months since I did this, so you may find other instructions or even an ISO somewhere, but I doubt it.

The CPU is an intel i7 8700k processor, thats what i meant by intel 7, sorry. I dont think this should have any bearing on peripheral operation during windows 7 install screen.

Additionally I called windows support today and after a half hour of symptom elaboration they had no solution. I ordered an older ps/2 keyboard so hopefully it will be recognized by windows despite the usb-ps/2 converter not powering the usb keyboard, which i am assuming is due to a problem in the converter itself. I might just try windows 8 instead.

Ok thank you, i will definitely apply this as soon as I can. However I dont think I can get online and copy the material until the initial install. Once the PS/2 keyboard gets here it will hopefully work and then i can get the usb 3 drivers