Just found this little gem of a site and I wanted to share it with you: YourBrowser.is.
Simply set up a free account with them to generate a link to send to your clients. Once your client clicks on the link, all their information will be sent to you in an email, like screen resolution and browser window size, and platform. No guess work. No need to spend time educating the client. It will all be right there in black and white.
Do you have another site that you use to check a client’s environment? I would love to hear about it.