|The auto power up might be due to a bios setting. That setting is 'Restore power after a power interruption'.|
If this is a new build, the power off might be due to using too much thermal paste on the CPU/Heatsink.
FWIW to XP users: When you click on the 'Command Prompt' you are just causing the 'Command prompt' to be displayed. This prompt gives you access to NTVDM.EXE, the 'NT Virtual DOS Manager'.