Why does my PC come across to be constantly downloading something??

I enjoy AVG installed, and Zone Alarm, i play alot of online games but getting really high latency making the activity unplayable, this is due to the PC constantly downloading something at a high verbs rate, i've checked the processes running menu and it says system unexploited is using 98% of cpu power, this is driving me nuts, any ideas??

Why does my PC come across to be constantly downloading something??

I don`t know getting windows updates? if so you can control when these updates come through by going to control panel and clicking on window updates and schedule a time
If you play online games, you probably enjoy file sharing turned on.
you might hold a virus that uses all of your hit space, that happened to one of my feeble computers, if you cant figure out how to fix it i would recommend support up all of your files and programs to disks and formating the complex drive, it will delete everything but at least you shouldnt enjoy the problem any more.
There are 3 possibilities (1) Windows is downloading updates(2) A Malicious software is running in the background(3) CPU is overheating.

(1) Schedule a time for window updates.(2) Use a licensed Anti-virus Program to scan and remove the infection(Believe me it works!). I am using a Trend Micro Office Suite That has be provided by our Service provider.(3) Use extensive Cooling and apply extensive Coolent gel to your Processor to provide added shield against heat-up problems...