I installed fresh, checked the device manager and the HD audio had the triangle like the pic above right from the get go. I installed some of the usual drivers, as well as sound and graphics drivers.
Here's the thing, When I tried to install the intel drivers, it says my laptop does not meet the minimum requirements, when it far surpasses. I guess I should have tried to install the intel ones first, but I don't think that would have helped because I got the Intel driver manager thing and it found nothing.
When I googled this problem, it was really common, not just on my type of laptop. Haven't found a solution.
Okay, you can download the latest driver here: Download Intel® Graphics Driver for Windows® 10 [15.40][4th Gen]
Before you install it (so you don't get the 'device is not supported' message) do this: go to device manager --> graphics --> Intel 4400 --> double click on it --> go to the driver tab --> Remove driver --> and mark the checkbox so the device drivers get removed.
Then it will most probably prompt that you have to reboot your device, do that, and then you should be able to install this driver.
Just to be sure, is there an AMD graphics card present too? (In some cases it's also present in the acer aspire e1-572G).