Vista 64bit Booting up Problems

Specs:
AMD Phenom II X4 920 @ 2.8 Ghz (Quad Core)
Nvidia GeForce GTX260
4GB Ram DDR2 @ 1066
500GB SATA II HDD @ 7200 RPM 32MB Cache

Hi, My PC has been reseting every few Hours. for the past 2-3days now and i got more Ram for my PC and since then i cannot get to my desktop without being in SAFE MODE, I don't know what else to do everytime I attempt to try without being in safe mode it gets to the Window Symbol just before getting to the Desktop and feezes for a few Seconds and then restarts...i think we figured it out its something to do with Windows and something is not booting up right...anyways i hoping someone can help me with this or point me in the right directection or something... oh and i cannot reformat unfortunally my DVDROM decided to die on during this im hoping to find a diff way, if not worst case scenerio, i Reformat when i get my new DVDRom and pray it works


-Thanks