ok
there have been a lot of changes in vista since XP.
i can not list them all however i can give you several examples of why this is happening
1. Disc defrag, this is permanently running from the moment you turn on you p.c
2. System restore/shadow copy, this is constantly checking your system for new software...ect and making backups of you system
3. Windows defender, this is constantly interrogating you system for any unwanted nasties and unauthorised start-up programs
4. Windows update, this checks you system to make sure you have all the latest drivers and software to be sure you system is as up to date as possible
5. Windows side bar, any programs/gadgets you have on your side bar automatically go into you start-up shell thus have priority at first boot
there are also many more reasons as to why but I'd be here all week telling you
check out the
they can help you loads in understanding vista and what makes it tick