[HELP] Clicking on links aking me to adverts

Whenever I do a search on various search engines i go to click me desired link and it takes me to various advertising pages not the website I was looking for. I then everytime without fail have to hit back and re click the link to get to the website. What is going on ?!?!?!

Can you post a link?

Have you downloaded any "codecs" recently at a sites request when you couldn't see an online video.

If you have you may have downloaded a DNS redirect Trojan

If that is so, post back and I can give you a link to Macworld on how to remove it

i may have done i cant remember now can ou post the link thanks