The X98 has no true factory reset.
Both Android and Windows have reset options which restore the particular OS back to it’s original state.
None of these affect the partitions, however.
If you know your partitions have changed and want to restore to your original state, you would have to:
1. Flash an Android ROM with partitioning. This will recreate all partitions, wiping out Windows in the process.
2. Reinstall Windows using a USB hub, 2 USB drives and a USB keyboard