only allow one instance of browser running ????

[v fox]

Hello --
Is it possible to prevent more than one instance of the browser running? We bring up IE from powerbuilder to bring an applet to life. We don't want multiple instances of the browser running on a client PC. Is there a way to prevent the user from opening multiple instances of the browser?
Thanks for your insight.

[Danny Mui]

I think it is highly likely that the operating system would not allow you to prevent a user doing what they want (like loading additional programs).
I don't know how the applet/browser jvm works, but if the jvm is the same for all instances of the browser you can have the applet display some message (detected via a static variable) saying you don't want to have multiple applets open. Lots of other fun stuff can be done too (IIOP/RMI etc).