Yes, it is important to respond and report the results of your investigation in any case.
As the account holder you may be responsible for any activities over the account connection regardless of whether you are aware of and/or have consented to infringing activities.
Therefore, if you do not find the file, this incident should be further investigated to determine and eliminate the source of the problem, especially because repeat occurrence could jeopardize your Internet access service.
In order to resolve this case and to avoid these types of issues in the future we recommend you take the following steps:
- Locate and remove/delete any unlicensed copyrighted content currently on your computer system (please keep in mind that if something was professionally created within the last 75 years, it is likely to be copyrighted).
- Locate and disable/uninstall any peer-to-peer/file-sharing programs currently on your computer/system.
- Be sure everyone that uses your Internet access account is aware of copyright infringement issues and does not download from any disreputable sources.
- Be sure your wireless network (if applicable) is secured with passwords and encryption and that those security measures remain in place, especially after any service interruptions, such as a power outage.
- Keep your virus scanning program up to date and running scans regularly.
- Contact an IT professional of your choice for further assistance, if needed, to implement the above and/or to determine how this activity occurred and how to prevent its reoccurrence.