Go to Start|Run and type MSCONFIG. If you have never used it this is the System Configuration Utility. Click on the Startup Tab...top of the window on the far right side. This shows all the items that start when the computer starts. At the bottom of that page choose "Disable all". This will require a restart but it will turn off any software that may be causing the lockup. If this fixes it, then you will need to restart only 1 item at a time until you find which one is the problem.