Network Monitoring Software

[Cheese]

So...long story short.
Got a pop up message from Rogers that I had exceeded my monthly allotment of GB (set at 95GB). I found this strange as my account starts on the 18th and runs through to the 17th of the next month. We rarely even get close to that number unless skypeing overseas or something along that line, which we are not at this time.
I called tech support for Rogers and he told me there appeared to be excessive uploading from one of our computers in the house >5-6GB/day...sending info outside? In our case that is simply not a fact. I change passwords regularly, and we always have up to date security software monitoring everything.
The tech suggested I install Network Monitoring Software on each laptop/computer being used and check in a day to see which one is the problem.
Does this sound correct...and if yes can you recommend software that a non-geek can use and understand as the root cause for this issue?

Thanks in advance for your geekiness.

/edit
Does this look a good tool to use?
http://www.bwmonitor.com/

[Rathji]

Spiceworks would work, and is fairly straight forward to set up IIRC, but it is serious overkill for what you want. Just install it on one PC and make sure it can scan and find the others.

http://www.spiceworks.com/

You could even do something as simple as run the "netstat -e" command and record the data already transferred and do the same the next day. Not foolproof though, as the computer will need to be on the whole time.

I think the best solution though would be flashing something to your router that would allow you to monitor it at that point, but I am not sure if that will identify specific IP addresses within your network.

Something like http://www.dd-wrt.com/site/index or http://www.polarcloud.com/tomato

[CaptainCrunch]

I was going to suggest spiceworks because its open source and pretty decent, but your only really using like 10% of its functionality in this case.

[mykalberta]

Do you have a wireless network? Maybe someone hacked the Havarti password.

The only network monitoring software I have used is winpcap I like it but its likely much more detailed than what you are looking for.

You should just be able to find out the 30 day rolling statistics from your router assuming its a router plugged into a Rogers modem.

[woob]

Originally Posted by mykalberta

Do you have a wireless network? Maybe someone hacked the Havarti password.

[sclitheroe]

Why not just power them up one at a time (and only one on at a time) until you find the one that causes the most activity via the LEDs on the router even though its idle? Since its outside normal behaviour for your network, you don't need to waste your time installing full-time monitoring software, just identify the culprit machine and fix it.

[Muffins]

If any of them are Win 7 machines then you could always just toss the Network Meter gadget onto your desktop

http://addgadget.com/network_meter/