What does " I’m not exactly sure how I got it" mean?
4-4 I had just finished writing a TV script and was rushing to print it when my computer up. No cursor. No script. No nothing. In a panic, I called my friend Neil, a computer consultant. It turned out that I had a bad spyware, and that’s what was my computer’s breakdown. He asked if my machine was slow, and if a new toolbar had suddenly appeared―signs of spyware. I’m not exactly sure how I got it, but Neil removed it. We take our cars to the mechanic for regular checkups. Why do we expect our computers to run without the same care?
What does " I’m not exactly sure how I got it" mean and what does it refer to?