
*Warning: Uninstalling Chrome this way will completely erase your bookmarks, saved passwords, extensions, and Chrome settings on your computer.
Be sure to select Also delete your browsing data.
Reset Chrome's settings (Programs you install can change your Chrome settings without your knowledge - resetting them will undo any unwanted changes without interfering with your saved bookmarks and passwords). Check for and uninstall any unfamiliar extensions. Try using Chrome in incognito mode, which disables extensions (If that fixes the problem, one of your extensions is the troublemaker - disable them all, then re-enable them one at a time to find the culprit).
Try clearing your cache, cookies, and browsing data. If necessary, update Chrome to the latest version. Only move to the next step if the problem is still happening: Perform each step in order, restarting Chrome after each.
Is something strange other than unblocked ads happening in Chrome? Some basic troubleshooting can help you solve the problem, or at least eliminate the most obvious causes to make finding an eventual answer easier.