When migrating Visual Studio projects from VS 2003 to VS 2005, I encountered the error:
Fatal error cannot open "LIBC".
I thought I'd post the solution to make it easier for others to find.
To remove the error, navigate to Configuration Properties -> Linker -> Input. Then, add "libc" or "lib.lib" under Ignore specific library. In earlier versions of VS it was set to libc.lib.
I found the reference on this page about migration issues: Migrating to Visual Studio 2005