First I put it in folder when is file .exe. Now I put it to C:\Windows\SysWOW64, but application have error, that not found this library.

I think in Visual Studio. I don't know details, it's my friend's library, I didn't create it.

I didn't add my library to references. Before (on x86) I didn't add also and it was OK.

I tried to build my project as "AnyCPU", x86 and 64 bit, results are always the same: "BadImageFormatException was unhandled". According to the guideline, I used CORFLAGS. After call: CorFlags.exe library.dll I have:

Error CF008 : The specified file does not have a valid managed header.

I am trying to use any DLL in Windows 7 64 bit version. It give me exception "BadImageFormatException was unhandled". The same .dll works fine with Windows XP. The .dll was written in ASM and built using AnyCPU platform. Here is the call in project:

[DllImport("library.dll")] static extern bool MyFunction(IntPtr hWnd, uint Msg, IntPtr wParam, IntPtr lParam);

Anyone has come across it, is there a way to resolve it? Best regards.