You may not like the following Tricky but if it as you discribe you be far better of this time with a format and clean install of WINDOWS.
Trojons,trackers poss virus, 80 processes. Files from five accounts to back up. Make sure there clean before even atempting to Copy and re-install.
5 user accounts is a handfull to look after when the systems is in a1 condition.The time being spent to sort that lot out i dont think is worth it.