@tholyn0809 Hi,
Which DLC are you referring to specifically? For most games, the DLC should be accessible from the Origin Client. Click on "My Games", right-click on the desired game tile and then choose "Show Game Details". On the next page, scroll down and you should be able to any expansions as well as DLC and initiate a download from there.
If there are still any issues, you might want to consider initiating a repair as the power loss may have corrupted the data during the former installation process. In order to do that, you click Back to library, right-click on the game tile again and choose "Repair".
Let me know if you are still experiencing any issues.
Cheers,
Nils
