i have an old win 3.1 application which refuses to run under w2000 saing it is win nt. i tried to use file monitor and registry monitor to see how it does "os detecting", but i guess these apps can't monitor 16-bit. is there any way to prevent from this app seeing real os version? ( it does run in win 98 booted from the same hard disk, so i suppose it doesn't simply check for certain files' presense). thanks.