Need assistance with Google Chrome

Hi,

I just have a few questions for Chrome. My main issue is that, when I search for something on ebay, amazon or just in google, I start to get advertisments of what I searched, you know, directed advertisment.

What I do is erase my internet history, cookies, etc with CCleaner; but when I open Chrome again my configuration gets reset, the pages I set to open when I launch the browser don't appear and the extention of "turn off the lights" (one where the screen dims on youtube) seems to get uninstalled.

So, the thing is I whant to erase the internet stuff, for less advertisement and just clear space, but not loose my Chrome configuration.

Thanks in advance.