Windows Vista Wont Boot!

[booyadiaz]

I just upgraded my pc to windows 7 and then i didnt like it so i downgraded to windows vista ultimate. After installation, It self-rebooted. Once restarted, it went to this screen.

  Booting "Windows Vista"

acpi
Vista Loader 2.1.2

_

Nothing happens after this, I cant press anything, no key works. I did a reboot to see if it works but doesnt. now my screen wont come on. I got it up after i took out power cord, pressed power button to release all power, then i plugged it back in. Now screen works. I try to access boot menu but i set a password i dont know. Can Anyone Help??

[btb57]

Shut down the computer. If you are unsure whether the computer is off or in Hibernation, turn the
computer on, and then shut it down through the operating system.
2. Disconnect all external devices connected to the computer.
3. Disconnect the power from the computer by first unplugging the power cord from the AC outlet and
then unplugging the AC adapter from the computer.
4. Remove the battery (see Battery on page 40).
5. Remove the real-time clock (RTC) battery (see RTC battery on page 46).
6. Wait approximately 5 minutes.
7. Replace the RTC battery and reassemble the computer.
8. Connect AC power to the computer. Do not reinsert any batteries at this time.
9. Turn on the computer.
All passwords and all CMOS settings have been cleared.