|Try this to see if it's one of the programs that auto startup that is causing the problem. Start msconfig > in the General tab select 'Selective startup' and deselect 'Load startup items'. Reboot and if it boots ok, restore the selections in the General tab and start eliminating things in the msconfig startup tab.|
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'.