How to Resolve Slow Startup with VISTA

Control Panel > Performance Information and Tools
Click the Visual Effects options in the left pane and have Windows manage for "performance".
Run the Performance Self-Tuning and Diagnostics: Provides instrumentation and services that support user-driven and tool-driven diagnoses of performance problems, such as media glitching, slow application startup, slow system startup, and network-related delays.
This tool is built into Vista and can be run from
|_|_Control Panel
|_|_|_System Maintenance
|_|_|_|_Performance Information and Tools
|_|_|_|_|_Advanced tools (in the left pane)

Windows Vista Event Viewer>>Diagnostics-Performance Log: This is an excellent place to view Boot Performance Monitoring, startup, shutdown, and other performance issues. Events 100-199 are specifically related to Boot Performance.
MainPathBootTime is a more relevant measure, calculating how long it takes for you to get to a usable desktop.
BootPostBootTime represents the remainder of the boot process, during which processes and services load in the background and you can do stuff with the desktop.
BootTime is the total time it takes for every system startup activity to complete. (MainPathBootTime + BootPostBootTime)

defragment the boot files:
Go to Start/All Programs/Accessories/Command Prompt
At the prompt, type defrag C:\ -b
Exit was defrag has completed