Idle Net Download 900 Mb In 8 Hours

Hi Recently i am facing a new problem with my airtel 128 kBps Unlimited with manual dialer. When I connect to the net and stay as it is 10 - 15 minutes then start automatically downloading and uploading show on my DU meter and it affect my real speed. Last day i just connect the net and after 5 hours idle net is download 900 MB. I am use Zone Alarm Interent Security Suite.What i do
Download the s/w called X-netstat to check which program is doing the data transfer. U can block or kill that connection using X-netstat.May be U got spyware. So also try a good anti spyware.
You probably have spyware / viruses on your computer... get the appropriate software and clean it up. And how the hell can it download 900Mb in 5 hours?
900MB of Windows Update? I think not. As vebmetal points out.. 900MB in 5 Hrs on 128Kbps? you can't even do that much on 256Kbps.
its seems to be a virus / spyware problem..... I recommend AVG free antivirus, and Avg Anti-spyware , do a deep scanning of your not sure how good is "Zone Alarm Interent Security Suite" `s Antivirus engine.

the latest edition comes powered with kasperesky engine. so it's pretty reliable.
I am use zone alarm firewall with latest & full updates.Run spyware & antivirus (not found any virus, spyware)900 MB is not download its download and upload.