I definitely understand needing to know what is using your data! The same web sites/programs should use the same amount of data on most any computer. Is it possible you have some different programs set up on the laptop? Anything that would do automatic updates or anything like that? Do we use the same internet browser on both?
Follow us on Twitter @VZWSupport
Both Windows 7, both Explorer, no automatic downloads. I even bought a new battery for the laptop thinking that might have something to do with it but it did not help.
Read through other posts, you are definitely NOT the only person having this issue. VZW would rather profit from the problem rather than provide the services promised. I recommend that you file a complaint with the FTC and BBB.