Virus website

I have Windows 7. Lately when using IE I get, in the address bar, [Personal Information Removed]
. When I click on thye "x" it takes me to a page where it offers an upgrade to Windows 7. I continue to click "x" to try and get out of that page and end up having to Ctl-Alt-Del to get back to normal.  In the Tsk Manager there is always a program running that says "offer."  And IE is shown as "not responding."  Help please.