This is a very frustrating because the problem is not usually apparent. There are so many issues that can cause this that it can be difficult to sift through all the possible issues that cause this head-meet-wall type of frustration. My issue ended up being completely undocumented and required hours of watching processes to figure out, but I will let you in on what are the most common issues and if those do not work, I will tell how I ended up finding my problem.
First, to give you an idea of what is happening (in case you do not already know) is that in Windows and just about every operating system, there is a concept called focus. The window you are currently working with and view is the window that has focus. Most operating systems have the windows without focus grayed out a bit. Normally shifting focus is not an issue because you just click on the window that you want to focus on and you normally will not even tell the difference. The issues lies is when you are in a full-screen application, like watching a movie or playing a game. When another application requests focus when you are in a full-screen application, it will minimize your application. This is the issue we need to prevent.
Update 10/21/2012: This problems seem to be still pretty common. This page gets several hundred page views a day. As such, some of the comments are extremely useful to look at, particularly one of the first ones from Steve. Best of luck! Ask questions in the comments and I'll try to be of help.
This is a pretty scary problem if you run into it. According to the guy at the Apple Store, it's a pretty rare one too. Being such a rare problem, it's not very well documented. It just showed up one time when I rebooted the computer. More or less, when your computer restarts, it's goes to white screen for a while and then it goes to a black screen with the white text "No bootable device -- insert boot disk and press any key" and hangs there. Restart the computer and it does the same thing. Needless to say, when you need to take an online quiz before midnight, you start freaking out.
Follow me if you'd like. It will mostly consist of the random things that I can't flush out enough to make a full blog post.
Recently I decided to hook my computer to my roommate's TV and sound system to enjoy some Splinter Cell on a screen larger than my own and a sound system better than the one the laptop has built in. After a little investigation, the set-up wasn't hard. All the screen set-up can be done via the screen resolution panel and to get the sound to work, you just need to go to the sound panel (from the start panel) and right click on the speakers and click disable. If this doesn't work, make sure your RealTek drivers are up to date. This should enable to optical sound and you should be good to go.
Disabling the sound was a whole different beast. I simply thought to go and re-enable the speakers via the same sound panel would be enough, but alas, the optical sound was continuously enabled (the red light never went off on the headphone jack) despite disabling the speakers. Here's the solutions I've found:
1. If you haven't already, make sure your RealTek and Boot Camp stuff is all up to date.
2. Restart you computer.
3. From Control Panel, go to the programs panel. Find Boot Camp, right click it, and click repair. Let the install wizard go through everything and then restart your computer. This is what finally did the trick for me.
After doing step 3 the first time, every subsequent time it was simply enough to enable the speakers and restart my computer and it all worked. From what I've read, Apple is aware of this problem (it's an issue that has to do with the mechanical trigger inside the headphone jack that OSX compensates for but Windows doesn't) and they should fix it relatively soon.
Hope it helps.
UPDATE 06/25/10: Now it's simply enough for me to re-enable the speakers. I don't even have to restart the computer anymore.
UPDATE 10/23/10: Apple has addressed this issue now. Update your Boot Camp and then it should be enough to right click the sound icon in the system tray, click playback devices, and then re-enable the speakers (which is the top of the two options on my computer.)
It was announced this morning that Valve, creator of Steam, Half-Life 2, Portal, and the Left 4 Dead series has intentions to release all of their games on the Mac platform. Mac users rejoice everywhere as they uninstall Parallels or Boot Camp. I probably won't go as far as to do that, but I'll tell you now that the Windows side of my computer is going to see significantly less use. And you want to know the best part of all of this? If you buy (or have bought something) on Windows, you can play it now on Mac free of charge and vice versa. In summary: all of the games you have already on Steam you can just download the Mac version.