No probs
Screen4 is a small screen making/altering programme that comes with Mach, you should see it in the Mach3 folder on your drive (screen4.exe)
If you double click that and then when it starts choose to open a screen, if you are using the standard it will be called 1024.set and you will find it by browsing to your Mach3 folder (screen4 should look there by default)
Once the screen is opened if you doble click on the DRO you want a box will open with various things in it one of which is the OEM code or it may even be set with the drop down list. If the DRO that you want is in the drop down list then all you do is choose that, if not then you need to enter the OEM code for the DRO. When you have done that just save the screenset and you are ready to go

I would suggest you save the screenset as a different name however, that way when you upgrade Mach it wont get overwritten with the standard screen. If you for exapmle named your screen rogerbsstt.set you would just open Mach, go to View menu then load screens and browse to Mach3 folder and choose your screen and it will load.
Now to the OEM code list, its in a thread I started, the thread has been stickied, ie it stays near the top of the forum and doesnt drop down like others do when no replies have been posted. Anyway if you click here you will find the list.
http://www.machsupport.com/forum/index.php/topic,6657.0.htmlAny more questions just ask
Hood