Monitor goes black after XP loading

[Guest]

Hello, I had did some changes in registry entry because CD-ROM was not shown in My computer. In registry I had delete the Upper & Lower level entries. When I reboot the system monitor goes black after XP loading and keyboard & mouse is not working. Is it possible the problem will be solve without installing the operating system.

 

[number13]

try holding the F8 key down during boot and start in safe mode, if you still have a display, go to Start, All Programs, Accessories, System Tools, and Restore the computer to before your changes