Have you consulted your scanner's user manual/documentatin/Help File?
Have you checked the website of you scanner's vendor for updated drivers and/or software?
Have you consulted the FAQ for your scanner if one is available at the support pages provided by the scanner's vendor (most vendors will have something of the sort for most of their products)?
Is your scanner program configured to start with Windows?
Specifically what aspect of your " ... scanner program opens, with no input from me" ?
What does it want you to do when it opens?
Under what circumstances does it open while you're surfing the web - all websites/pages, or just certain ones or types (and if just certain ones or types, most typically which ones)?