Internet scam heads up

Just a heads up. I have just received a call on my land line claiming to be from windows technical department. They tried to get me to download some software, claiming they had detected a virus on my PC. having called Bt they told me these calls are comming from over seas (india or pakistan) and cannot be blocked. So just a heads up iof you get a call hang up the phone.
There is info online if you search internet scams.