Sorry for replying to an old post.
Silvercoupe, thanks for the pepreload script. I understand the principle, but when I try to use it, it does not show a popup. It just stops. When opening a command prompt and starting taskmgr, and show processes for all users, I do find the wscript executable. After killing it the OSD process continues. Apparently the popup in my testscript (msgbox "test") is active, but just not showing.
When I start taskmgr, I see about 8 tasks under user system. When selecting show form all users I get a lot more, but most of them also run under the system account. I tried to copy it locally and start it from x:\windows\system32, but no joy. If I start a command prompt (in WinPE) and start the script from there it works fine, so I added the vbscript engine correct. I have no clue how to make the script start in a visible way. Did I forget something?