You don't know if the application was VB, VB.net, C, C+, C++, C#, C.net, or something else and can't find source code? What is the file extension of the application? Windows 7 won't run a lot of older programs. I believe often has to do with 32bit vs 64bit compatibility. Abandon it and write a new one.
I use a simple VBScript to copy, open, run Access project. Create script with Notepad, save file, rename so the extension is vbs instead txt. This makes the file an executable.
Code:
Const OverwriteExisting = TRUE
Set objFSO = CreateObject("Scripting.FileSystemObject")
'following will copy Access file
objFSO.CopyFile "\\your file path\your file name.accdb", "c:\", OverwriteExisting
'following will now open the Access file
Set oShell = CreateObject("WScript.Shell")
oShell.Run """C:\Program Files\Microsoft Office\Office12\msaccess.exe"" ""c:\your file name.accdb"""