Have you contacted and advised the school's IT Department?
In most school environments, the IT Department
implements specific policies and procedures for the use of computer equipment and related resources. These official procedures are designed and implemented to provide security and certain restrictions to protect the network. This allows all users to safely use school resources with minimum risk of malware infection, illegal software, and exposure to inappropriate Internet sites or other prohibited activity. If you have an issue, then you need to resolve it with the IT staff or school administrators. We will not assist anyone with attempts to bypass those policies or security measures
Further, if the machine is infected, the IT staff generally has procedures in place to deal with malware infections to protect the network and school resources. Further, the malware you are dealing with may have already infected the network. If that's the case, the IT Department needs to be advised right away so they can take the appropriate measures.