Yes they are able to tell if you are on a certain computer.

Anybody can.

You'll be surprised how much information is provided by all browsers.

What they do is log key items of information and if it changes they say they don't recognize the computer. Doing a lot of cleaning via something like ccleaner can trigger it. Adding or deleting programs can too.


Patrick T. Caezza
Santa Paula, CA 93060
C-7 - Low Voltage System Contractor - Lic# 992448