boot up freezing

when I turn on my computer screen that lets you go into the bios by pressing the delete key stays on for at least 10 seconds, (it usually stays on for 3 seconds). Then windows loading screen comes on and when the windows flag appears it freezes and 2 minutes later it loads and everything is fine. I have eliminated all non essential programs from loading while booting up and it still happens. I checked the bios and everything seems to be ok. The voltages out of the power supply are good according to the bios. I am running windows 7 64 bit home edition. Any ideas will be appreciated. Thank you.