Samsung Galaxy S5, 32 GB memory card, conservative app set (it's mainly a work tool). I use the GPS a lot to locate work sites, I check my E-mail (but usually reply, if necessary, from desktop at home), Have Avast Mobile Security installed. Use Chrome when I need to browse (relatively infrequently, usually to look up something technical). For as long as I can remember, clicking the "internet" icon brought me to Google Chrome open at the Google search screen (which was usually where I wanted to be). Now all of a sudden (well, a couple of weeks ago or so) the Internet icon has changed (it is now dark purple with a negative image of a globe on it) and it opens ad marketing sites - in endless variety. For a while it began with adsmarketinghub.com and quickly morphed to electronics ads, then tried to sell me an iPhone 6, etc. etc. etc. The only way to get out of the ads is to hit the "recent" button at lower left and then x out of the ad site currently displayed - or to turn off the power.
If I go to apps and choose Google Chrome it takes me to Google Chrome, which then works in the normal way. So my question is, can I get rid of whatever has hijacked my "Internet" path? I have scanned with Avast! Mobile Security, the scan comes up empty and says everything is safe. Is this just a matter of finding and resetting the default "target" in Google Chrome? Or what is going on here?