Why isn't my Acer Aspire 6920 switching over to its external monitor with Fn+F5?

You may have to go into my computer and properties and disable its build in monitor to allow

the external one to work

This is a shot in the dark here, but you may have your external monitor improperly configured.
Since your Acer monitor will turn on, I'm assuming it's functional.

First, lets get the very basic stuff out of the way. Make sure all cables are hooked up securely and that the power to the external monitor is on. If there is no signal, the LED might be orange. You could also try using a different VGA cable.

Now for the real stuff:
Right click on your desktop, go to "Properties" and click on the "Settings" tab.
You should see two "screen-like" boxes in the grey area. Click on Number 2 screen, and try adjusting the resolution for it, preferable the Samsung's native resolution if you know it. If you don't know the native resolution, keep trying different ones. If you don't see two, press Fn+F5 and wait a few seconds. Press them again if you still don't see two.

If it recognized the monitor once, it will recognize it again. Since it was the first time you turned it all on, it was trying to search for a proper configuration, and might have not done a great job. By manually setting up a configuration, you might be able to work around this.

Well, even when I press Fn+F5, the 2nd monitor option isn't showing up under the settings tab. It's working completely fine in all safe modes, but when I put it in normal mode it stops working. It loads fine on the Samsung monitor up until it's time for the log-in screen to pop up. I have a Dell that I'm using now that works perfect with the monitor. =( I tried unlocking sticky keys but I didn't see how that would've been a problem... is there a way to restart all of the options for the Samsung monitor and start over completely as if I just took the monitor out of the box?

It sounds like something has happened to the graphics driver for the Acer.

Have you tried turning everything off and back on again?

If this doesn't work try reinstalling the VGA graphics driver which you can get from here
http://us.acer.com/acer/service.do?LanguageISOCtxParam=en&miu10einu24. current.attN2B2F2EEF=3750&sp=page15e&ctx2.c2att1=25&miu10ekcond13.attN 2B2F2EEF=3750&CountryISOCtxParam=US&ctx1g.c2att92=453&ctx1.att21k=1&CR C=2054404012

This is not a problem with the monitor, it's a problem with your settings on the Acer.
Since it's showing output on the monitor while booting, we know the connection works perfectly. It's just a matter of getting Windows to use the output, more specifically, your video card.

I searched around and found that this particular laptop has an Intel GMA X3100 video card which is integrated into the motherboard. This means it's nothing special and does not have a utility program controlling it's output as an ATI or NVIDIA card drivers would. Although Windows software does still control this through software, there has to be a solution.

Thankfully the manual might provide a clue.
-First, plug in the computer to a wall AC outlet. This will ensure that there is nothing enabling power-management features.
-Launch the Windows Mobility Center via the control panel.
-A window will pop up divided into different categories including one for the display.
-There will be an "External Display" if nothing is present, click on the "Connect Display" button and let me know what happens.

I've been looking around online while waiting for answers from you guys and someone suggested to go to the menu that comes up when pressing F8 as the computer loads and switch to a lower resolution. I did that, the 640 by such and such.. and that seems to allow the laptop to switch over to the monitor and let me log in, it goes to my desktop then within 3 seconds it switches back over to the laptop, never to be seen again on my Samsung. So, maybe resolution issues?

Also, I can't access the control panel because I can't see on my laptop screen at all. And since it won't switch over to my Samsung monitor I can't do anything outside of safe mode. Unfortunately, the windows mobility center isn't available in safe mode.. =( I've already tried...
I'm having the worst time with this Acer...

Maybe I should just reboot the whole laptop?

Thank you all though for your input. I appreciate it so much!

I suspected resolution issues as we know the output is working. How about hooking up the Dell monitor and configuring the secondary monitor resolution through that display?

I wouldn't recommend reinstalling everything on the laptop as this won't solve anything.
When you pushed F8 on startup, did you try selecting VGA mode?

Also, what is the model number of the Samsung

This answer was edited by mwilly 15 days ago.

Reason: add

Meh.. how do I do that?

Well if the Dell is a laptop, then you can't use that monitor for your laptop. But I sorta assumed it might be a tower PC, which in that case you could unplug the monitor from the rear of the computer and plug it into the laptop.

Try my added suggestions to my previous post, and please give me the model number of the Samsung.

No, the Dell is a laptop..
The Samsung model is 933SN.