An old Win16 application, Harrapsf.exe (dictionnary) used to work fine under win 2000 (and win 95...).
However, under XP, it worked fine for a while - a few weeks - then could not start anymore, giving a program internal error (33400). User was Administrator.
After creating another Admin account (admin2), and selecting "Run with different credentials" the program run fine again for a few weeks, as "admin2", then gave the same error...
So I created another account ! (admin3) then again ... and so on... works fine for a few weeks, then have to create another admin account, run the prog under its credentials...
According to A thread (they're rare!) the problem is linked with printers.
I have one USB printer connected.
Does it ring a bell to somebody?
PS: by the way - it may not be related - if the program is loaded and run for a long time, e.g. a week, it eventually crashes, throwing another error something like "The Win 16 Subsystem has insufficient resources to continue running. ...." then have to close it and it does not start anymore until next reboot (the same error insufficient resources comes) ; while there is 1 GB physical RAM available :)