I have the same problem. Here is what I did: I downloaded a No Cd hack and I put the files War3.org and replace my War3.exe with a cracked one. I go to Battle.net and it says it needs to update, so I let it update then it says it will restart the program. I click ok then about halfway on the Blizzard updater it says: "Error, invalid the file's checksum does not match, to fix this problem please try re-installing the game."---Well I borrowed the game from my friend all the way across the state and I already mailed it back, plus bought a cd-key for 3 dollars so thats how I installed it. Is there any way I could fix this?
