Tanya, I can't say for positive, but I really doubt that problem is going to be forum related. At least, nobody posting bug reports on the vB website ever mentioned something like this, and there are lots and lots of people testing the software.
You might try downloading two programs from downloads.com . One is called Ad-Aware SE and the other one is called Spybot Search and Destroy. They're on that website's main page, down near the bottom at the right. The problem might be being caused by adware or spyware that has attached itself into your Windows. Those programs will check for that stuff and get rid of it. Try running the scans then rebooting your machine and see what happens.