iMac black screen how to make 2nd screen primary

Hi, my IMac 2008 2.4 ghz intel core 2 duo has the black screen, i have connected an external VGA monitor and I have mirrored screens, but because i cannot access the iMac primary screen i cannot change the primary screen to the external monitor. Thus I cannot open files etc. How can i make the external monitor my primary screen.. any keyboard shortcuts?

Thanks in advance

Hi Kyle K, thanks for your reply, i already used the command f1 to mirror screen on my VGA monitor, so i can see display but cannot see or open any files or see my MacHD folder and applications on the side bar aren´t opening now either, my problem is when i go system preferences and open displays i have the mirrored option on, when i uncheck mirror display box my vga screen goes blank, my understanding is that to change the primary screen i have to uncheck mirror screen and move the white bar and adjust screens but i cannot view that option. hence the request for keyboard shortcuts to make secondary monitor my primary.

my applications dock is visible but cannot open any of the applications

hey KyleK, my iMac screen has the black screen, my vga monitor is mirrored by command f1 so i can now see apps dock and screen background image but can't open any apps, also my machd is nowhere to be seen, yet i can open system preferences from the apple menu top left, also finder doesn't work, any suggestions?

----------

i see you mentioned in another post about accessing drive with target disk mode, whats that?

because i can't use my iMac screen, when i go system prefs, display, i can only select mirror option, if i uncheck that box to change primary display i lose that display prefs window, earlier i managed to access the apps dock but can't now. earlier the files saved to my desktop were showing but i couldn't open them by clicking on their thumbnails, but could via finder, but now i can't open any apps or files. I just came back from mac repair shop, they said my iMac screen was no good and out of date to replace, they suggested attaching an external monitor which i have, i bought the via adaptor, clicked the command f1 yet its not working properly.

----------

my iMac has the black screen issue problem, i haven´t unplugged the external monitor since i first connected it to the iMac. According to the mac repair guys my iMac was working fine otherwise

----------

however i can access the top white menu bar with the apple menu, wifi, volume, time, username etc, i can open apps and files with the magnifying glass at top right of screen too, yet apps dock is not working and machd is missing along with the files previously saved to desktop

----------

update: now having clicked on magnifying glass top right and opened apps from there, my dock apps are now opening and via that search window i can open files, yet the machd and desktop files are still missing and i cannot copy files anywhere. i have garageband open and cannot drag and drop audio files into it.

----------

i also cannot drag and drop files from finder window to quicktime app in my dock

----------

by magnifying glass i mean Spotlight

here is a screenshot, this all works but no machd or desktop files, also cannot copy or drag and drop from finder window.

this the view on my vga external monitor, iMac is black screen

KyleK thanks for your help bro, i don´t know where my machd desktop icon folder is, but it seems i will have to find a way around this issue and the drag and drop problem, cheers

Hi the screen problem resolved itself after a restart, now its working , i can see and open MacHD, copy files etc. Command f1 works. Thanks for your help