So, here's the situation: I have an early 2009 17" Macbook Pro. The screen has sadly been broken for some time, so the laptop stays at home with an external monitor constantly plugged in and I use it only in clamshell mode. I wanted to do a clean install of the OS, so I backed everything up, created a bootable USB and went into settings to have the laptop boot from USB. Shut down the laptop, booted from USB...and the external monitor remains blank. The actual laptop screen is lit up - I can't read anything on it though so I don't know what is displaying - but the external monitor turns off and says that it doesn't recognize my laptop anymore. I've tried starting and restarting, but the external monitor is never recognized. I have a USB mouse and keyboard plugged in, but those don't seem to wake up the external monitor at all. I tried unplugging and plugging back in the external monitor, with no luck. I've tried several keyboard commands to try and wake up the external monitor: fn+f1, cmd+fn+f1, fn+f7, fn+f2....all with no luck. I've done some research online to find solutions, and the only suggestion I've found is to plug in an external mouse/keyboard and use those to "wake up" the monitor. I've tried that, but without any luck. Does anyone have any other ideas? Thank you for any suggestions!