Try this. click here it will tell you if any drivers are needing updated.You can always go elsewhere to download the drivers needed,I have used it for about a year with no problems.
Maybe your security programs updating at start up.Maybe set them to run at a later time.
msconfig and make sure that there are no programs running at start up that you do not need.
Not sure if a reformat would need a defrag but it was advisable if you had to download SP3.