uninstall everything cc including preferences, https://helpx.adobe.com/creative-cloud/help/uninstall-remove-app.html
then uninstall the cc desktop app, https://helpx.adobe.com/creative-cloud/help/uninstall-creative-cloud-desktop-app.html
clean your computer of cc files per http://www.adobe.com/support/contact/cscleanertool.html
restart your computer (don't skip this)
reinstall the cc desktop app, https://creative.adobe.com/products/creative-cloud.
if you're unable to install the cc desktop app at this stage, use an administrator account (solution 3 here, https://helpx.adobe.com/creative-cloud/kb/creative-cloud-missing-damaged.html)
use the desktop app to install your cc programs/trials
It didn't work. I uninstalled EVERYTHING Adobe-related and installed the cleaner (which I thought would work and it seemed to have done something) and the most I got was it hanging at 74% the first time. Now it's back to 40-42%. What if I just bought it instead? Is it just a problem with trying to download the trial?
no, it's not just a trial issue. at 42% of install means the download has completed and extraction of the downloaded file (in one of your temp or tmp) folders is starting.
that could be a permissions problem, space problem or something like an antivirus program problem.
using a browser that allows popups and cookies, contact adobe support during pst business hours by clicking here and, when available, click 'still need help', http://helpx.adobe.com/x-productkb/global/service-ccm.html
How can I access the temp folders while the program is attempting to download? I managed to download the setup file but I don't know where to go from here.
are you using the cc desktop app from here https://creative.adobe.com/products/creative-cloud to install?
if not, do so.
if yes, using a browser that allows popups and cookies, contact adobe support during pst business hours by clicking here and, when available, click 'still need help', http://helpx.adobe.com/x-productkb/global/service-ccm.html