I just installed a WD hard drive in a older model HP 8755C that runs ME on it. I finished the install but have a problem, or at least a question. When the system booted up it goes to a black screen and "operating system not found" appears as the message. Does this mean I need to reinstall ME or have a made an error on the HD install? Another problem is that I don't have the original ME installation discs but rather ME recovery discs which was all that came with it. What should I do from here?