ok for starters oh mr genious, the “CLOUD” storage there talking about is 100% what i am talking about. SC2 DOES NOT HAVE CLOUD STORAGE. There talking about microsoft cloud, but again you probably didnt read all the reply’s where they are telling the op poster to reset HIS CLOUD, Mr. Genius.
Now again im going to say this for the last time, sc2 campaign progress is stored on YOUR PC. It is stored in the DOCUMENTS FOLDER. IF you dont believe me, why dont you open up your documents folder and check for your self. Go to documents click on sc2, click on the name that you use and oh gee gollly would you look at that, it has SAVES, REPLAY, BANKS folders as well as your campaign progress xml document that tells the game where your progess is at. Geee mr genius, hmmm, btw when you redownload and reinstall Sc2, it only reinstalls the game files, not your account files. The only account files stored by blizzard itself are if your playing a paid account, and where your rankings and stats for ladders, coop, and achievements, thats it. This is why if you download the game to a different pc and tried to play campaign with out copying your files from the original comp to the new comp, campaign will reset to zero.
Also, you said why is your game stuck on those same mission and all that after reinstall, its becuase when you install the game, it reinstalls and wipes the games files location in your comp, which for most people in the Cdrive program files. however to prevent losing progress in the game and all that, they do not obliterate your saves and replays and all that, becuase it can only create the files in the documents folder for sc2 user info, but not remove and destroy it as it is a seperate file system that is created after the game is installed, and since you already had those files created in the first place, sc2 will not replace any existing data or overwrite the old data in said folders. Its basically does an “oh you have those folders already, ok, no need to make new ones here, we will just skip this part then.”
So as to maybe fixing your problem itself, the most likely solution would be to delete the campaign xml document and hope it just resets at square one. You will most likely lose all your progress but atleast you would be able to progress as something in that file seems to be corrupted, maybe a corruptor got in there and puked on it or something.