Windows 7 Computer boots slowly and strangely

I just got Windows 7 today, and I really like it. One thing I noticed though is that it doesn't seem to boot faster than Vista, although many reviews said that it did. I did an upgrade from vista to windows 7, so my hard drive was not wiped. Everything loads pretty quickly except for when the PC reaches the Welcome screen. After about 30 seconds of the welcome screen the main desktop comes up, but still loads everything slow. My keyboard displays what % of the CPU is being used, and when the desktop comes up, it drops to about 3-10 %. Why does the CPU slow down so much when it still has to load gadgets and desktop icons. Is there something I can do to improve the boot time? Thanks, and sorry for this huge message.

Oh, and also, Windows Media Player crashes when I try to play a .avi video.