Vista to 7 – help and advise needed

Hey guys.
I wanted to upgrade from Vista (home premium) to Windows 7 so I downloaded Win 7 ISO from one of the post here and burned it using Imgburn (4x speed). When I put that DVD on to my Vista laptop (2GB Ram 32-bit) it gives me an error saying: \sources\spwizeng.dll is either not designed for windows or contains an error. So i thought I burned the disc wrong, but the same disc works on my other win7 latop (it asks me to install it).
So now I have 2 questions
1. How do I go about upgrading/clean install my Vista home premium to Windows 7 ultimate (its possible)….what link should I use (links to the post will be great)
2. What am I doing wrong here….
PS: What backup system to use in case of a clean install…
Help please
Thanks guys
Answer #1
http://answers.microsoft.com/en-us/windows/forum/windows_7-windows_install/tried-to-load-windows-7-upgrade-on-my-vista/86cf4408-81bf-406b-ba96-f63154f5a1b5
Answer #2
thanks….i did a clean install