Today I spend about two/three hours on the net and download about 200mb of videos but according to my ISP I have used 1,200 mb. I use pop-up blockers, tracking blockers etc. Any ideas why this is so?

I just get the feeling that the more bandwidth you buy the more you mistorously "use" in just general viewing of ATS and a few other websites.

Well, thank goodness the internet is OK!!

Do you know if your ISP counts uploads into your data use? Mine does, it never used to, we had on peak, off peak, and uploads were a completely separate count. Now I have this fancy "Anytime Quota" which basically means "We've actually removed the good stuff like not counting uploads into your quota, now your uploads do count as a total, and we've also removed allocated times when you have two separate quotas, on peak, and off peak, and we've done it in a sneaky that will make you WANT to go back to a prehistoric useage method, by calling it Anytime Quota, and you will lap it up.. Oh and also, you don't have a choice!"

Also, most ISP data use counters aren't exactly up to date. They update periodically but won't always reflect an exact current usage compared to what you think..

try using a bandwidth monitoring utility that tracks all your internet usage and can give yo a tally at the end of the day/week/month/year etc.. good for keeping track of what you actually use. As long as you're the only PC on your home network.

No hard or software information = Windows System.

Advice: Boot into safe mode, do an AV scan, not the quick one but scan your whole system, ALL drives, remove malware as adviced by your AV program.

Chances are your box is ridden with spyware / malware.

If this doesn't reduce the suspected unauthorized bandwith use, you should look into either re-installing from the scratch, or use Wireshark to specifically find out which process is using which ports to doenload what type of data.

ETA: Or simply get a friggin' flat-rate if the above is too much of a hassle.

Try changing wireless network password. Someone else might be using it.