Assuming you are running Windows. Many private servers have their own type of hardware ban etc. It can be difficult to find the exact values/files that needs to be deleted or edited. You can however always use the following methods:
1. Use another computer/laptop
2. Install a virtual machine (Oracle VirtualBox is free)
3. Reinstall Windows
4. Restore your system to a point before your ban. Delete all the private server files/cache. Clean your computer up nicely. If the ban still persists: do this at your own risk: change the MachineGUID to an acceptable value (you must research this yourself, as there are many different versions) under: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Cryptography\MachineGuid. If the ban still persists: change all values in HKEY_LOCAL_MACHINE > SOFTWARE > Microsoft > Windows NT > CurrentVersion (Google this for guidance: Change Windows Installation Date and Time.)