Dragon Age 2 won't boot up.

I'm having the same problem and I've also been unable to fix it.

GreyWarden22​ 

What do you mean by "I've tried to boot the game back up"?
Before this the game crashed at a cutscene, was that the exact same cutscene every time? 
Do you use Mods? 

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I'll try to contact them again and tell them nothing worked, they said they sent a report to the team but I've not gotten any follow up response on if they fixed the issue.

I'm really sorry that it doesn't work for you cus it's a real bummer to not be able to play the game you paid for. I don't know what else to suggest other than contacting EA themselves cus it's their fault to begin with. you could also try searching the forums to see if there are any other solutions that might work.  

I'm trying to delete all of the temp files but some of them just won't delete. I've tried rebooting and nothing worked, still went on with the whole revouninstaller trick a second try and it didn't change anything. Are you sure this works because I'm still getting the same results.

yes deleting temp files is completely safe don't worry. by the way, I had to do the whole thing twice for it to work because the first time I didn't restart immediately after deleting the registry keys and when I checked the issue still persisted, so giving it another shot and doing everything in the exact order might do the trick. I'm currently still playing and it hasn't bothered me again since I fixed it.

I just did everything you listed, literally nothing worked, still getting the exact same issue.

I assume deleting the temp files won't mess with my other apps? Are they where all of the caches are in?

i'm having the same issue here for the past hour and i've tried everything as well, and I mean EVERYTHING and I still can't get it to work. 

UPDATE:

I somehow managed to make it work again by following holger1405's solution step-by-step: 

Please clear your temp files:

• Press the Windows key and "R" at the same time to open the Run dialog box.
• Into the new window, type or copy & paste:  "%temp%"  (Without the quotes.) > hit "ENTER"
• Now your Windows Explorer should have brought you to the "C:\Users\>your user name<\AppData\Local\\Temp" folder. > Delete all files and folders in it.  
  (If some files or folders can't be deleted, reboot and try again.)

Then:

• Go here and download "Revo Uninstaller. (The freeware version, Portable version works too.)
• Run "Revo Uninstaller" > EA app.
• At the end of the main uninstall, Revo will ask you which cleaning method you want to use. > Select "Advance" > Browse.
• If "Remaining registration content found" is displayed > Select All > Delete > Next
• When "Remaining Data and Folders" is displayed > Select All > Delete.
• Restart the PC
• Download a new EA app setup exe from here. (Do it even if you already have the installer!)
• Install EA app.
• Run EA app as Administrator > Click the EA app shortcut on your desktop > Run as Administrator. 
• Test. 

this worked for me thankfully but another user pointed out that the same issue appeared again the next day, and when they tried to repeat the steps, it didn't work anymore.

link to the referred discussion: https://forums.ea.com/discussions/dragon-age-franchise-discussion-en/ea-launcher-canceling-da-game-launch/12289774