start up problems iPhone 3G

so my phone went off today when i got a call and the screen was blank.
i tried to slide the slider and nothing happened.. it didnt even say slide to unlock!. nor did it ring, it just vibrated..
so i had to do a hard shut off and when i started it back up it gets stuck on the apple logo then the little spinning circle pops up and gets stuck then shuts off and restarts again.. this happens 3 times then it starts up fine?
has anybody had this problem? any fixes? also when it started up fine i tryed to turn off the phone and turn it back on to expect it to be gone and NOPE! it happend again..
HP Windows Vista ugh!.. need a new one.. and wuts up with the new iphone??