Used in conjuction with GetModuleFileNameEx:

            GetModuleFileNameEx(p.Handle, hMods[i], strbld, (uint)(strbld.Capacity));

static extern uint GetModuleFileNameEx(IntPtr hProcess, IntPtr hModule, [Out] StringBuilder lpBaseName, [In] [MarshalAs(UnmanagedType.U4)] int nSize);

Public Shared Function GetModuleFileNameEx(ByVal hProcess As IntPtr, ByVal hModule As IntPtr, <Out()> ByVal lpBaseName As StringBuilder, <[In]()> <MarshalAs(UnmanagedType.U4)> ByVal nSize As Integer) As UInteger

static extern uint GetModuleFileNameEx(IntPtr hProcess, IntPtr hModule, [Out] StringBuilder lpBaseName, uint nSize);

            GetModuleFileNameEx(p.Handle, hMods[i], strbld, (uint)(strbld.Capacity));

I found this to be more comprehensive than GetModuleFileNameEx. Didnt need to enumerate windows or modules

static extern int GetModuleFileNameEx(IntPtr hProcess, IntPtr hModule, StringBuilder lpFilename, int nSize);

Declare Function GetModuleFileNameEx Lib "coredll.dll" (ByVal hProcess As IntPtr, ByVal hModule As IntPtr, ByVal lpFileName As System.Text.StringBuilder, ByVal nSize As Int32) As Int32

static extern int GetModuleFileNameEx(IntPtr hProcess, IntPtr hModule, StringBuilder lpFilename, int nSize);

Declare Function GetModuleFileNameEx Lib "coredll.dll" (ByVal hProcess As IntPtr, ByVal hModule As IntPtr, ByVal lpFileName As System.Text.StringBuilder, ByVal nSize As Int32) As Int32