Thanks Dennis, I believe something has been corrupted. I have uninstalled 7.0 for the time being, however every time I start LabVIEW 6.0.2 now the "windows is preparing to install" dialog flashes up, and then msiexec.exe is running continuously in task manager. (I also noticed this when running exe before removing 7.0) I don't know what has caused this. Basically the garbling consists of tab controls transparent but operable by clicking on text, boolean controls invisible, and control borders invisible... I think I will reformat at this stage, unless you know what is causing msiexec to launch each time? I will attach the msi log if you care to take a look. I will try reinstall of rte as well