till you can track it down. Also keeping unplugged from internet might kick an error msg leading to some discovery of what's up. You should check tasks running and see which one is using CPU power the most or constantly. Check your Activity and Error logging in Events area.
After I boot my XP PC and log in, the "local area connection status" shows typically 7 million packets of data sent, and just 25 packets received. Is this normal or does it suggest a virus/spyware? I have AVG Free installed and a recent scan is clear. I also scan regularly with Malwarebytes, again all clear. I also installed SpyBot, and that gave a clear scan, though I removed it afterwards because its essential service would not start automatically as supposed to.
On one occasion, when my PC had been on for a while, there was a flurry of disk activity after which it said 30 million packets sent. That's a heck of a lot of data, about 2GB if I'm right in thinking the packet size is 68 bytes. Anyone any ideas? I've installed Tcpview to see what's going on, but by the time I'm logged in it's all over!