Have you downloaded a toolbar at all? Toolbars often change your home page to match, and it might be what's linking you to ads.
have you downloaded any hacked clients or some dodgy things try remove them if you can find them (usually Hacked things do)
Check your settings, and see if you have any ad blocks, if you do, switch them on, and if not, download some. I don't have a Microsoft computer, I have a mac, but that might work, not sure.
This happened to me as well. Go to your settings in Chrome. Check out the homepage tab in settings, make sure it's set to your usual page. You may also want to go to control panel and then uninstall a program. Look for the name or something like that and uninstall it. Hopefully this helps o;