Priority one, is all your personal data, artwork, etc., backed up to a secondary, separate removable hard drive? (Or, perhaps something like amazon cloud drive.)Once your data is safe, then at least the worst case scenario should be the annoyance of an OS reinstall.On a related note, making periodic whole-system snapshots with software like Acronis True Image gives one the option of rolling the entire OS back to the state of a previous backup. (Keeping one's personal data on a separate HDD partition than the OS makes this process the least painful.)As for troubleshooting the network traffic, perhaps something like https://www.glasswire.com/ would help show exactly which processes are causing the traffic.(There are also more technically-oriented tools like https://www.wireshark.org/ .)