I have an application that requires a lot of memory on my PC. I am running Win XP Pro, SP2. The application runs under DOS so I have to use the ?Command Prompt? subset of windows. The problem I am having is that I am using a debug program from Microsoft for the Fortran language and it takes a lot of memory. I believe that Windows only will allow a maximum use of 3Gig of memory and I actually have 4Gig of memory. When I run the program, I get an ?Out of Memory? error. How can I use more memory under the Windows Op. Sys.? Any ideas will be appreciated.