I have an established application that has been working well, untouched, for years now.
The application runs on a server in their office via a mapped network drive.
A client recently upgraded to Windows 7 64bit (new hardware).
She works in my app, keeps it open and switches between Outlook and Word etc.
Sometimes when she switches back to my app its "Not responding" and it has to be force closed.
The app doesn't do this with me (Windows 7, 32bit), but its the only software that does this on her PC - so she blames my software. I have no idea where to start.
Can anyone offer advice?