The usage records are kept indefinitely unless you delete the records or lose the database, say in case of a hard drive replacement.
You can see what apps and IP addresses used the most data, but not specific pages on a web-site. This is available in the
Applications and Web-sites report described at the bottom of
this page.
Regarding your other questions:
- Use the Reset button, it resets everything and deletes all records.
- The Reset button deletes all records and allows you to start from a specific volume of downloads and uploads. This is usually used immediately after installation. For example, if you know that you had used 5 GB this month before you installed NetWorx. Then you enter 5 GB when doing a Reset, and NetWorx reports match those of the ISP from that point onwards.
- Most likely because no data was recorded for those dates. These two reports require the Ignore LAN traffic option to be on and data collection is only possible from that moment. For example, if you have turned this option on today, there would be no data for any prior days.
- No, it is kept in %ALLUSERSPROFILE%\Application Data\SoftPerfect\NetWorx, in a standard SQLite3 database.