Install Vista RTM to a secondary partition ( not the main boot partition).

For those of you who want to slipstream Vista SP1, this may be the only way to do it as Microsoft does not provide any switches in the SP1 executable to allow for simple integration. The disadvantage of this method is that it requires a complete install of Vista RTM in order to integrate the service pack. However, there is a method of repacking the install.wim to make a Vista SP1 integrated media image. Right now the word is that this should be supported in future service packs. Microsoft had originally planned to make the system of integrating a service pack into Windows Vista an easy task by supporting integration into offline images, but because Microsoft made some significant changes, this is not supported in SP1. Slipstreaming is usually done on network shares on corporate systems, but it also makes sense for the home or small business user to do.

Slipstreaming a Service Pack is the process to integrate the Service Pack into the installation so that with every new installation the Operating System and Service Pack are installed at the same time. Slipstream Windows Vista Service Pack 1 By: Arie Slob

Microsoft windows vista service pack 1