Vista Booting up Delayed in Studio1557

my machine came along with windows7 home premium which i don't like. so once i received it i installed my vista ultimate 64bit (no SP). then i updated it to sp2. but the annoying thing what i noticed is booting time.

Once the Dell logo disappears i can see couple of blinking on the top left corner then screen goes off and should pop up booting, but it goes off and stays like that for 30secs then starts booting process. it's annoying. i tried many way to sort it out. in BIOS Quickbooting option is enable.
i had Studio XPS1645 for a week and that machine gave me the same problem. and because of that with some other reason i returned that machine and got this Studio1557 with i7 processor. does any1 aware of this issue? how to sort it out. it just taking my time. plzzz help me with advice as quick as possible.

 

Check your event viewer for some bad services that startup automatically. That's what happened in my HP, it took like 5 minutes to boot.

P/S: Well, you're the first guy who doesn't like win7 and maybe vista is just slower than win7

 

I don't like Win7 because of it's start menu style. i hate that style and also there is no Dreamscene which is something extra in Vista. and also i have got some other cause, i can't exactly remember. anyway, i will keep win7 as well in another partition. and will b using it on and off. well, i'll have a look on what u said. right now i m updating windows. Oh!! one more thing, Vista takes me around 32gb with all update installed including SP2(System restore Untick). do u have any idea how much it should take?

NB: I still didn't install any software, so i don't think there should b any bad service in start up. i checked msconfig and saw only some application starts up like synaptics, IDT, bluetooth. by th way, shall i change core 1 to 8 in advance booting option?