Remove user access to the sharepoint 2010 site collection

Hi,

I have an account which is used to install sharepoint and required software in my standalone system (distributed also). I don't want to grant any access to this account. For that I have followed below steps.

1) Removed from Farm administrator gruop

2) Removed from Site collections group

3) Application pool identity also changed with some other user

4) Removed complete access from Site Permissions page

Still when i check permissions for this user using "Check Permissions" in Site Permissions page, it is displaying all the permissions which is shown in below screen shot.



Please help me out how can i remove this user access to the site collection.