Recently a tool called vLite has received quite a lot of media attention. This tool can be used to make Windows Vista installations more lightweight by removing several components and implementing various performance tweaks.
As expected Microsoft warns users for this tool as it can affect your system's stability:
Although the move does offer frustrated Vista users an option other than going back to XP or switching to a Mac, Microsoft said Wednesday that it doesn't endorse such changes to Vista's setup.
"Microsoft does not recommend using any tool to strip out applications from Windows Vista prior to installing it on your system, as it may affect your ability to download future Windows updates and service packs, and may cause your system to become unstable," the company said in an e-mail to CNET News.com.