ehow has a good tutorial on How to Get Your Computer to Boot Faster, which recommends to perform the following steps,
- By loading only the required software at system startup, you can cut your boot time significantly.
Stop unwanted programs that start up automatically on Windows by configuring “msconfig” utility.
- Change the “Timeout” in “BOOT.INI” tab in MS Config to 3 seconds. (It is typically set to 30).
- Keep your anti virus software up to date, install an anti-spyware like Lavasoft’s Ad Aware (free for private use )
- At least once a month, clear browser Internet temp files, empty your recycle bin and perform a disc defragmentation
- Set up your computer to go into standby mode automatically after a certain amount of time. (Do this in your control panel setting)
- Establish hibernation mode , better choice for an overnight shut down.