Once you've installed Windows Vista Service Pack 1 and you're confident it's working, you can reclaim almost a gigabyte of storage by running the Windows Vista Service Pack 1 Cleanup utility. To do this:
- Open a Windows Command Prompt (Start, Run, 'cmd', and press 'Enter')
- Type "vsp1cln.exe" (without the quotes).
- Press 'Enter'
You'll get a "Would you like to continue" prompt advising that without the files you're removing, you'll not be able to revert to the pre-SP1 version of Windows Vista.
The utility removes the setup files and backup versions of pre-SP1 bits.
Caveat: Don't run the utility unless you're convinced your Windows Vista installation is functioning optimally. You cannot regress to the pre-SP1 version once you've tidied up.