Group Policy for different users

I do not understand why can’t get 1 PC to have different settings in Group Policy then the others. I made a separte OU named WinXp, I then made a group in it called WinXp and put 1 PC in it. I then made a new GPO for the WinXP OU and changed my IE home page (as a test).
I then went to the my main domain OU and denyed access to the WinXP group and then for the WinXP GPO I gave read and apply GPO access. On the WinXp GPO I even put Block Policy inhert.
I refresh and restart the D.C> but it still doesn’t change. I do not get the new IR page and I still get the settings from the main domain GPO.

I am just trying to set it up so that users or objects in one OU are different and don’t inhertite from the other one.