1. you should delete files in safe mode
2. in the newly created account you may not have transfered the data from the old account properly to work in the new account.
3. have you checked your permissions for the file you want to move or delete?
4. if something is in use you cannot move or delete, which is why it would be good to use safe mode as the minimal is loaded.
5. if your scans have not found anything, and the issue has persisted for an extended period, you may have an infection that is too deeply embedded to find. There are some malware removal sites I can direct you to if you like.
6. as a last resort you can reinstall your os and start fresh.