I was prompt to install Windows Update Service Pack 1 for vista, during installation, my PC just crashed with blue screen that says: "a problem has been detected and windows has been shut down to prevent damage to your computer. A driver has overrun a stack-based buffer. This overrun could potentially allow a malicious user to gain control of this machine." then in the bottom of the screen, it says " collecting data for crash dump, initializing disk for crash dumpm beginning dump of physical memory, dumping physical memory to disk, physical memory dump complete."

I tried to boot it on a safe mode with command prompt and typed rstrui.exe, but its giving me the only restore point as the serivce pack 1, I can't even do it manually to choose other restore points. I don't have a recovery disk to boot up vista.

What should I do now?

Hi Angel, welcome to NST.
the SP1 restore point is probably the one it took before starting the update. (it labels them with the name of what it's about to do)
Try selecting it to get back to pre-SP1. (restores are fully reversible anyway, so you shouldn't be any worse off, and hopefully it will put you back in a position to try again.)