The Dell System Software listed on the downloads for the 1525 are for Vista 32 bit.  There is no Windows 7 version listed.  Have you tried installing it in Compatibility Mode for Vista?   I assume this is what you want, it's still unclear exactly what you want to do.
Hello, everyone. Im new here in this community forum, but i got a problem. I have Dell Inspiron 1525, and Windows 7 Ultimate then i dowloaded kind of drivers then System Software but it won't install, then this message:  This Microsoft Windows operating system service pack is not supported. Please update to the latest Microsoft Windows service pack.   I've installed Windows 7 SP1 but it gives me the same problem.   Please anyone help me.
Dell can't install System Software on Windows 7.