Unable to Start Game After Trying DEP Fix. [SOLVED]

Hello! I'm using Windows 7 Ultimate and have had no prior problems with the game. Only recently I have been having problems with my game crashing while in CAS so I've been working my way down the list of crash fixes. I followed the instructions for the DEP fix but now I can't get my game to start at all. I have tried to start it via the launcher and the error that I get reads: There was an error during start-up. Please see log for more details.

I have tried to start it by clicking the .exe film and the error that I get reads: Unable to start game. Service initialization failed (0x0175dcbb).

I'm not sure what my next step should be, so I'd appreciate any help on how to fix this problem and my game. Thanks!

Ok, I have watched this video. Will this work even if I still have all of my EP's installed? I haven't removed or changed anything. Thanks!

In the video it says to remove the key for whichever expansions you do not have currently installed. I have all the expansions installed so should I still do this? I'm just trying to understand and avoid a total re-install, sorry if seem dense. Thanks.

Thanks for your help Shamrock! I had to go ahead and uninstall and reinstall the game, and it works fine now. But, thanks a bunch for your prompt assistance.

No thank you! A re-install fixed all.