Another thing to check is the number of programs that load during boot. The easiest way I have found to manage this is with Startup Manager. Download at the bottom of this site - startman.exe

If you let software and Windows xp do their thing, a couple new system will have a dozen or more unnecessary loading during boot. They range from Java to media player to print trays, etc. None are necessary. If and when one is needed, it will load at that time.

The only things that load at boot on my machine is my AV program and desktop.ini