To locate the file for a module that was loaded by current process, use the GetModuleFileName function.

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

To locate the file for a module that was loaded by current process, use the GetModuleFileName function.

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

public static extern uint GetModuleFileName

Public Function GetModuleFileName(<[In]()> ByVal hModule As IntPtr, <Out()> ByVal lpFilename As StringBuilder, <[In]()> <MarshalAs(UnmanagedType.U4)> ByVal nSize As Integer) As UInteger

If you want to use GetModuleFilename to retrieve the path the current executable was started from, you should instead consider using System.Windows.Forms.Application.StartupPath. This is a wrapper around GetModuleFilename, so it probably does exactly what you want.

        DllFuntions.GetModuleFileName(IntPtr.Zero, fileName, fileName.Capacity);

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));

This can be used in place of the GetModuleFileName call, which doesn't work on processes that haven't been loaded by the current one.

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