SQL SP4 installed but not showing @@version

I am trying to install SQL Server 2005 SP4 on windows 2008 R2 SP1. Right now I have SQL Server 2005 x64 Standard Edition SP1. I did try to install the SP 4 couple of times but whenever I checked the @@version it’s still showing me SP1.
I download this version of Microsoft SQL Server 2005 Service Pack 4 RTM and trying to install with no luck.
I check the hotfix summary and its shows me below results:

Prerequisites Check & Status
SQLSupport: Passed

Products Disqualified & Reason
Product Reason

Your help is greatly appreciated. Thanks

Hi iqbalbutt1,
Did you check the installation log? Did you get any error message during installation?