I had a similar problem when running LV7 on Win-XP Pro. At the time, I was having and another problem. When solving the other problem which was related to the Labview Active-X server, the memory problem disappeared.
I also had 512 MB of memory and upgraded it to 1 GB. It had not solved the problem. Some of the steps I recall were: 1. Re-install Win-XP & LabView. The reason was that a registry file may have been corrupted at one point. 2. Change the DCOM Config settings to allow full permissions over LV & TestStand files (to resolve the Active-X server problem). I can't remember what else I did. Fortunately, the memory problem disappeared. I never figured out why I had it in the first place. I also cannot remember changing the vi's... Good luck, -JLV-
