I have an internet plan with a maximum usage of 80 GB a month which is more than enough to suffice me and my family ( 2 others in the house ) for internet usage for the month. However, our ISP has just informed us the past two months now that we are reaching AND going over the 80 GB limit which is impossible for just the 3 us. We do not use the internet to download or upload massive amounts of data, so I am beginning to become suspicious.
We have one main PC ( which I custom built a long time ago ), which is connected to the modem which has a wireless router built inside. There are two other laptops which connect to the router for internet access in the house. The network has a randomly generated password (something like 15 characters) and it is WPA2 protected. I am not suspicious about someone else using our internet network, I have a feeling that the main desktop PC is infected with some sort of spyware/adware/virus and that it is draining our usage to the max. Is this possible? I did google the topic and found that if I try using the " netstat -ano " command in command prompt, that I can verify what is connecting to the internet ( at least I think this is what that does ) I also tried to match the PID of some of those connections in task manager - processing tab. Some matched up, but about 5 or so did not. I am not sure how to get rid of these processes for good or what step I am to take next which is why I came here.
Is it possible that the computer is infected and our usage is being drained by the infection? Is there some software that I can run that will let me know that there are suspicious connections on the computer and how to get rid of them? I should also mention, that when I did the " netstat " command, i was told that there should be almost nothing displayed (only a few connections ) but there at least 20 items that appear.
If anyone can provide any help at all it would be greatly appreciated.
I can provide specs. for anything if needed as well.
The main desktop PC is running windows 7 64 bit and mcafee antivirus expired about 3 days ago ( getting renewed).
Sorry for any information I have missed, writing this in a hurry...
Thanks in advance!