French Ads Appear on Web Pages

Ideally something like Crap Cleaner should be used

http://www.filehippo.com/download_ccleaner/

Along with your Normal AV and Malware Scans.

So you should install & update any required applications then reboot in Safe Mode and scan the system with whatever it is you use as an Anti Virus product and Malware Scanner.

Ideally you should rescan till either the system is clean or you can not remove something then proceed onto the next application to scan the system with.

If you don't have any AV or Malware Scanners you can use AVG Free

http://free.avg.com/download-avg-anti-virus-free-edition

As a AV product and then Malware Bytes

http://download.cnet.com/Malwarebytes-Anti-Malware/3000-8022_4-10804572.html?tag=mncol&cdlPid=10878968

Spy Bot S&D

http://www.safer-networking.org/en/download/index.html

To scan the system for Malware. Also don't forget Crap Cleaner or as it is now called CCleaner.

Also open the Control Panel in Classic View and make sure that the Region Setting is set to your country and isn't set to some French Speaking Country.

Col

Maybe you have a French IP?

There are many IP finder sites that will tell you where they think you are:
http://www.google.co.uk/search?sourceid=navclient&aq=0h&oq=ip&ie=UTF-8&rlz=1T4GZHZ_enGB231GB231&q=ip+finder