E:\INSTALLED GAMES\Wacraft III\save\Profile1
E:\INSTALLED GAMES\Wacraft III\save\Profile2
E:\INSTALLED GAMES\Wacraft III\save\Profile3
...
You can delete and add the newest campaign and still you have your saves. There shouldn't be any problems.
Just start the latest chapter you played and use give up. You get your gold in chapter 1 then. Doesn't matter what version the campaign is.