If my boss received a complaint letter about me, how can I defend myself and what rights do I have?

At a college where I work, a student wrote a complaint letter toward me regarding a friendly casual conversation that I had with female co-worker on women's issues. The conversation held no derogatory comments or obscene remarks but was objectively stated and absent of personal depictions. My boss after receiving this letter told me that I could not come back to work or get paid until the matter is solved. I will also not be compensated for lost time and salary. I have worked non union status at this college for five years, have a spotless record, and get along with everyone. There's been no copy of the letter presented to me, nor have I had an opportunity to defend myself.