My computer won't start up past the Windows screen. sony vaio notebook?

[lili5689]

Yesterday my computer froze when i tried to restart it from hibernate mode, and I had to reset the BIOS to get it back up. When I woke up this morning my computer had shut itself down and now it won't come up past the Windows loading screen. It takes a long time for Windows to load and as soon as it is going to the login screen it restarts and does it all over again. Sometimes a box flashes that says "the operation has failed" and then it restarts, other times the screen just goes black and it restarts.

When I press F2 to try to start it in safe mode or start it at the last working configuration, it won't allow me to scroll up or down to choose an option, and just chooses to start normally after 30 seconds.

Sometimes when it chooses to start normally this message comes up: "STOP:c000021a {Fatal System Error} The Windows Logon Process system process terminated unexpectedly with a status of 0x00000402 (0X0000000 0X000000). The system has been shut down."