Hi, I downloaded the trial version of Adobe Acrobat ... However, when I run it, I am told that there is 0 days left on the trial. Please help!

there's nothing easy (eg, you can reformat your hd, reinstall your os and then start a trial) that you can do to correct that on the problematic computer.  you can start a trial on another computer.

here's more info (that may or may not be helpful), https://helpx.adobe.com/x-productkb/global/trial-software-expired-early.html