Okay, so, I've looked everywhere and cannot find anyone with the same problem as I'm currently having.
In Mass Effect 3, I tried to load up a save on the Normandy. That worked fine. Then, I tried to go to the Captain's Cabin, which resulted in a never-ending loading screen. It didn't freeze, it didn't crash to desktop or present any type of error message, it just refused to cease loading. I decided to simply start a new game with a recent ME2 character I just finished.
Everything was going fine until the end of Priority: Mars. I killed Dr. Eva, Shepard grabbed a very hurt Ashley and they all boarded the Normandy. The screen faded to black...
...and stayed there. It never returned to the game.
This hasn't happened before and it's getting on my nerves. If it somehow helps, I just uninstalled ThaneMOD (although it was installed when it happened on the Normandy). I also just bought and installed the Digital Deluxe Upgrade.
As of right now, I'm replacing the current folders in my ME3 root folder with the back ups I saved after a fresh install a couple days ago, hoping it'll help somehow.
If there's anything anyone can tell me, I'd appreciate it. I'll let you know if I find a solution on my own, in case anyone else encounters the same issue.
Edit: Replacing the files worked. Still don't know what could have caused it, though.