Application Changes
1. Remove SendKeys calls and replace them with API code.
2. Use the HKEY_CURRENT_USER in the registry for the settings of your application. Do not write to HKEY_LOCAL_MACHINE.
3. If you are using ADO use 2.8 and above in your application.
4. If you are using XML use XML version 3.0 and above in your application
5. If you are using the PlaySound API, if your wave files are not PCM but mpeg layer-3 make sure your mpeg wave files are Stereo and not Mono.
6. If you need the Printer Setup dialog either using the Common Dialog Control, or by using the API functions, the dialog will not return the correct number of copies. The dialog will always return 1 on Vista. The way around this bug is to create your own Printer Setup dialog box and when you get the correct number of copies you will have to send to the printer multiple times to print out multiple copies. Here is a link that discusses this issue in details.
7. Relocate settings files, data files etc into "Common Files" (C:\Users\Public) instead of "Program Files". You should use the API calls to locate these folders because the folders are in different paths for different machines and OSs. Here is a link that discusses this issue in details.