When you made these modifications, did you modify a copy of the existing .USR file or did you modify an FP7 file and then rename it to have the .USR extension?
When you create the runtime solution, you are asked to specify a "binding key" that the runtime app uses to identify which files are bound to it. If you opened the .USR file and modified it, it should still have this binding key and should still open correctly when you replace the older copy with the new. If you started with an FP7 file, it won't have this needed key.
I modded an FP7. If I open the runtime solution, it opens. But if I save as and save a new file, the runtime solution won't open it. But it tries to open .usr with adobe and I can't change it.
"But if I save as and save a new file, the runtime solution won't open it"
From the runtime or from FileMaker Advanced?
Is this with the .USR file open or with the .FP7 file open?
Modifying an fp7 file leaves out the binding key so you'd need to create a new solution using a binding key. If you do that and use the same key as the first time, you can just drop the newly created .usr file into the existing runtime folder and it should work.
Filemaker Advanced is not loaded on the laptop running Vista only the runtime solution. On my desktop I'm running Windows 7. I'll take it completely off the laptop, then install the newer runtime version and see what happens.