How to find the cause of a traffic leak in Windows XP?

Question

Computer networks

A computer with a USB 3G modem, left for the New Year holidays, spent a fair amount of traffic, which led to a certain amount of money.
How to understand what exactly spent the traffic? There is no additional software on the PC that would monitor the activity of the operating system, where do you even start?
Traffic in portions every 6 hours, 60 megabytes per 25 minutes
As I understand it:

1. check for viruses, not found by Casper and 360 Total security
   
2. in the Windows logs check all events at the moments of the traffic jump according to the billing
   
3. check operating system update log
   

Answer 1

1. Windows:
- constantly checks for updates, and the volume of traffic can be quite significant
- constantly merges the accumulated data ("knocks"), especially a dozen
2. Browsers:
- constantly checks for updates on themselves and plugins
- if it was open, they constantly support connections to sites
3. All other software:
- constantly checks for updates. Everyone suffers from this - from Adobe Reader to some hundred-kilobyte stuff, the difference is only in the size of updates :) If it was a laptop, then usually laptop manufacturers install their own "super-useful" software, which also constantly climbs to the manufacturer's website and checks for updates on themselves and on laptop...

Answer 2

How to find the cause of a traffic leak in Windows?

Take a printout from the operator and see from which addresses, when and how much was downloaded.
It is not clear what the viruses have to do with it.
And it is not clear what volumes of traffic we are talking about.
For a modern computer, it is quite in the order of things to download from nothing to do 10-20GB per day.

Answer 3

Well, put wireshark or something similar to monitor network traffic and see where and what flies.

Answer 4

Networx is much simpler than Wireshark for monitoring traffic, but you need to look for version 5.5.
Since the new 2017, Networx has received an upgrade to version 6 (nothing has changed) and has become paid.