I'm currently developing win32 applications for x32 OS (Windows XP Pro - Windows Server 2003) and I use Visual Studio 2005 on 32 bits OS (Win XP Pro/Windows Server 2003). I would like to move on a 64 bits WinXP Pro because of the supported amount of RAM (I would like to move from 3 Gb to 8 Gb). Will I be still able to develop my applications for 32 bits OS without problems (simply telling to Visual Studio to build for x32) or will I run into troubles ? Has someone already tried this ? How hard will be to fix the eventual problems I will have ? Thanks a lot for your help. A.