Why is my google chrome keep redirecting my site to an advertisement site?

Sounds like you are infected with the same rootkit virus I was. These viruses are very good at hiding themselves from antivirus software. But there are some tools out there that look specifically for these things and remove them.

The 1st one to try is TDSSKiller.exe:

http://support.kaspersky.com/viruses/solutions?qid...

If that doesn't do the job you can try Combofix (I used this to fix my redirect problem):

http://www.bleepingcomputer.com/combofix/how-to-us...

Oh, and to reduce the chances of a virus like this installing itself again in future, you should update Java (I heard it installs itself by taking advantage of a vulnerability in a previous version of Java). To do this open Control Panel and (in classic view) open the Java Control Panel. On the Update tab click the "Update Now" button. Enabling automatic updates for Java is also a good idea.

Google Chrome Redirects

I just went through hell with the same thing, you have the "Google Re-direct virus" and it's hell to get rid of. Tried everthing, even At&t online tech, they finally had to run restore and got it out.

you got a hijack virus - run malwarebytes.org