There was no errors before until now. :\

Code:
1>------ Build started: Project: Run, Configuration: Debug Win32 ------
1>  Run.cpp
1>LINK : fatal error LNK1561: entry point must be defined
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
Yes, I am using c++ visual 2010.

What did I do wrong?