Crashes as soonas I try to add text field to fillable PDF--Adobe Acrobat X Standard

Background:

--I purchased Adobe Acrobat X Standard years ago and have happily used it on my Windows computer for years without a problem.

--Unfortunately, I messed it up while cleaning up my computer and had to reinstall it

--I reinstalled it this morning (with a link from Adobe Tech Support)

Problem:

--Now I cannot open or add text fields to Fillable PDFs

Symptoms:

--I can open a normal PDF

--But a Fillable PDF crashes as soon as I open it

--And if I try to make my own Fillable PDF from scratch, it immediately crashes when I add a text box, check box, etc

Request:

--Please help me understand what's the problem with my current version of Adobe Acrobat X

--Please help me create/edit a Fillable PDF

Thanks!!