If your pc is slow on boot there are numerous factors to consider.....
Low HDD space
Small amount of memory
Generally a low end Slow pc (what is your pc spec?)
Lots of startup items
the list goes on.......
To speed up my boot i usually use a couple of applications like tune up utilities 2008 and ace utilities version 4.
You can however achieve good boot up speed by using MSCONFIG
Go to START - RUN - type msconfig and press enter.
The screen you will see after this is a thing of beauty.
Find the startup tab and click on it
this will list everything that starts up when your pc starts, untick the ones you know you dont need/want starting.
for example: Quicktime.
Press ok and exit with restart.
Run an anti virus scan.
Run Spybot S+D (The home of Spybot-S&D!) its free!!!
Restart the pc
Try timing your pc before and after these operations
Post back with your results
thanks