Why do i keep getting thewrong web page?

hello can some one please help 9 time`s out of ten i get the wrong web page opening for me like i type in facebook get you tube opening in stead and pages offering tips to save money and dating pages have done all the checks for virus anti malware checks but they all come back clean is there some other way to check to see why this happens and how to fix this hope some one can help new to the pc so need the allthe help can get