You commented your daughter is at a “top university”. I have a rising sophomore at a T20 school who is a STEM major. I don’t know how grading is done at your D’s school but introductory STEM classes at my D’s school rarely are graded on a “normal” scale (60 for D, 70 for C, etc.). My D has gotten quite low scores on tests and assignments and still ended up with good grades in the class. She took a physics class this spring where test averages were in the 50’s. So, while a 64% may not be great it also may not be a D.
If your D’s school is known for having a challenging STEM curriculum, taking some of those classes might have been a mistake and you might want to be thankful she had to pass/fail them At my D’s school the first CS class is known to be a killer, and that’s for kids who are majoring in CS. That is not a class non-CS majors generally take.
One last point: Trust goes both ways. You are upset she lied to you but you went on her computer and logged into her computer to check up on her. Seems like you all need to have a talk about what you have access to and what you don’t.