can anybody tell me why this error happen?? fatal error LNK1120: 1 unresolved externals error LNK2001: unresolved external symbol ...
If that's the exact error then your linker is broken because it should tell you what symbol is missing so that you can find it. OTOH if you've just removed the symbol name for some reason then what this means is that the linker has looked through all the libraries you've specificed and not been able to find the symbol. So you need to find out what library defines that symbol and add it to the link line.