The computer may well contain evidence to support the contention that you committed criminal offenses in relation to the police report and restraining order. It is difficult to guess what is on your computer, or what remnants are likely to remain of old files or temporary Internet files that have been deleted. The prosecuting authorities would not be executing a search warrant and examining your computer if they did not anticipate filing criminal charges in the event that they uncover incriminating evidence.
Arguing that child porn simply appeared on your computer, and presumably organized itself into folders, is probably not credible. Viable defenses to the presence of such files usually involve evidence that somebody else was responsible for their presence - either maliciously, through shared use of a computer, or through the failure to notice a prior owner's files on a second-hand computer.
You should retain an attorney, experienced in these matters, as soon as you can.

