Hello, recently my comp has started not to reboot (really). On issuing the reboot command, it terminates all the applications & comes to windows is shuuting down, & then the screen goes blank.... with the CPU light still on & nothing happens until i have to turn off the power supply. I made two changes to my system before this happened:.. 1. REplacing tcpip.sys to change max. tcp settings 2. Setting activate time for auto start in BIOS settings. Are these responsible for the change?