I cannot open the installer and I don't know how to find support so here I am

I get "error 112: not enough room on disk"

However, my disk that the installer is filed to has over 600GB. I cannot imagine the installer needs more room than that. The disk I installed to is my storage disk, not my main C drive though. But i have no way of redirecting the installer if it's trying to automatically go to the C drive. Please advise.

If you select the Advanced install mode, then you can specify the folder where it installs to. It should only use the main drive for some temporary files during installation.

It creates a log file in the %temp% folder. That may reveal where it goes wrong. How much free space is on your C drive?

If your C drive has a low amount of free space, then it may be smart to change the location of your temp folder.
Windows Control Panel > System > Advanced System Settings > Environment variables

Admin wrote:If your C drive has a low amount of free space, then it may be smart to change the location of your temp folder.
Windows Control Panel > System > Advanced System Settings > Environment variables

I changed both temp folder locations (thank you, i've been trying to figure that out for days) and at first it brought up the installer. I clicked off the basic startup and it gave me a features list, nowhere did it ask me where to install. So of course when I clicked "next" it told me the selected drive was too small to install to. But it never asked me where to install it. So I aborted it and went to try the basic version, maybe it asks me where to install? Nope, now it won't even start the installer. it just tells me the same thing: not enough space on the disk.

Apparently I get one free try per new download. Once I try to install and it gets all the way through the entire advanced questioning, (without ever asking me WHERE to install) it tells me there's not enough room on the disk then shuts down. After that, I cannot retry the install from the same download. So clearly changing the temp file helped but I cannot figure out how to tell the codec installer to put it in the drive I downloaded to. Is there a button, question or trick to opening the installer that allows me to set it's destination? Cuz I'm not seeing it anywhere. I've tried it with four different downloads

At the very beginning of the installation you can choose between NORMAL and ADVANCED installation. You need to select ADVANCED to choose the installation folder. If you already have the codec pack installed, then uninstall it first.

If you have so little free space on your C drive, then Windows may not function properly either.

You may be able to free up some space with cleanup tool:
Start > Run > cleanmgr.exe
(tip: click on "clean up system files" button to clean extra things)

I swear to you, I chose "ADVANCED" installation. Nowhere was I asked to choose the destination file.

I'll try the cleanup tool. How do I uninstall the codec pack? I assume you mean the original? Not the upgrade I'm trying to install now? Does it have its own uninstall or do I just use the W10 uninstaller?

rather, when I "open as administrator" I unclick "quick setup" - that is the only time there is a way to get into it. Still, nowhere is the option to change the destination folder. When I go through all the options, it tells me the destination folder is C but there is no option to change that. This is maddening.

cleanup netted me 1MB of free space.

Finally got it: had to search for it, but found the uninstall and deleted the entire program. When I reloaded the updated installer, it asked me. FINALLY.

Thank you.

Correct. When updating it uses the existing location.