Jared is proberly right about your app being single threaded. If you are absolutely shure you have tried multiple threading and the problem is still there, you encountered another problem. In this case it's very likely your 'large process' is eating up all the system cpu resource. This does cause other applications to hang too and you will probably only have acces to the windows task manager. At least untill you process has finished. To avoid this kind of problem, you will probably have to lower the process priority of your 'large process' its threat. I don't exactly know how to do this in C#.NET. I hope this helps you a little further, but be shure to check first whether or not your app is really multi threathed.

You could also make use of unsafe coding by using the unsafe keyword. Make shure to set up the compiler options for allowing unsafe code in the project. For further instructions check the help provided with your c# package.

You could also open Regedit.exe. Go to "HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\Run". Add a String Value. Set it's name to whatever you want. Let it's value point to the pad of the program you want to run. Enter something like: "c:\windows\explorer.exe ??" where ?? are optional commandline-arguments you would want to use. While this key is originally designed for Win9x it should also work on XP. At least it works on my XP-version. Of course you could also add such a value by using a .reg file or you could let the installer you use for deploying you application do this for you. I'm not shure whether or not someone needs to log on first before the application gets started, but it works for all users. I hope this helps. Roland.