Windows 7: laptop picking up unwanted background audio

I ran a virus scan and everything was clear.
Just turned laptop on to reply to this and immediately had an advert for M and M's!
What is puzzling me the most is why all of a sudden should this start happening? I have had my broadband for years and never had this before.
Surely there must be something I can do to block these unwanted background adverts out?

Yesterday I suggested this:
Before trying anything else can you connect to the router using a cable and switch the wireless connection off?
have you tried it?

Not knowing what scans you have run. I would suggest running these.
Malwarebytes
http://www.eset.com/us/online-scanner/

If I connect a cable to the router and turn the wireless off how will I connect to the internet?

If you use an ethernet cable (it will have sthe same shape plug each end with a little plastic clip to hold the plug in the socket so that when you want to remove the cable from the laptop or the router you need to depress that little clip. The cable will be brightly colored, red, blue or yellow ) You cant put the plu in the wrong socket the laptop socket will be easy to identify anf the Router will probably have four places where you can put the plug. It doesn't matter which one you choose. They will be numbered 1,2,3 and 4. any one will do) You will then be automatically connected to the internet.
Connecting via a cable is a more robust way of connecting to the internet and is much more reliable. You might also notice an increase in speed. if you ever have internet connection problems always try to resolve it using a cable connection, then sort out the wireless if you need it once the actual internet connection problem is sorted. If you always use your machine near to the router then use a cable connection all the time.

Unfortunately my laptop location is nowhere near my router to connect via ethernet continuously.
I have ran a Malware program and it detected several Trojans.They have been removed yet I am still getting ads so that has not solved it.When it was running I noticed bits of games that I played months ago and have been uninstalled,that were still showing up,how do I remove these bits that have been left behind? Maybe something has attached itself to one of these remaining bits?

Can you not try the laptop near to the Router so that you can try a cable connection? I feel the wireless connection on your Router migh just be picking up a local commercial radio station and a cable connection will be the only way to prove this. If this does prove to be the case then we can look at getting rid of the signal at the router not at the laptop, if that makes sense.

sportagegirl if you would just do what mitchell65 has requested 3 times it would allow us to guide you. We need help from you in order to help you. If for what ever reason you don't want to just tell us and we will get on with helping others.