Buddy of mine took my explaination to him and posted it, just clarifying a few things I didn't tell him.
This trick works great for playing warcraft 3 with no cd, in case you want to have a LAN party but only have one cd, however if you have not purchased warcraft 3 do not use this to play your leaked retail on battlenet, support blizzard and buy the game.
This only works for windows XP as any other operating system will not allow you to rename a file that is in use (i.e. war3.exe) also if you would like to make it easier on yourself a create a batch file to rename the files rather than alt tab and do it by hand everytime I will briefly explain how.
Basically take the cracked war3.exe file (which you can find at many places including
www.gamecopyworld.com ) and rename it to war3a.exe, then place it in your war3 folder. also have your normal retail war3.exe in the folder. then open notepad and type the following (cut and pasting this will work too)
rename war3.exe war3b.exe
rename war3a.exe war3.exe
start war3.exe
rename war3.exe war3a.exe
rename war3b.exe war3.exe
after you have this entered click file save as in notepad and save it in your war3folder as war3start.bat or something of the sort, as long as the .bat is there your alright. then just double click the .bat file and it should rename the real .exe to B then it will rename the cracked to war3.exe and run the cracked, right when the game launches it will rename the cracked back to A and the real .exe back to just war3.exe causing the game to think its still running it. remember this only works with windows XP. You also NEED a legal battlenet/blizzard CD key in order to play, so if you don't have one, tough, buy the game. hope this works, post with questions.