ASP.NET machine account???

In trying to fix a problem I ran across an account under manage other accounts' ASP.NET machine account' I do not know what this is or where it came from but changed the password just to be safe. Can anyone tell me what it is.Also I have another problem and Windows MEDIA CENTER keeps launching each time I put a DVD in the drive but i would rather use MEDIA PLAYER. I can't seem to be able to get the thing to stop doing it and have tried everything. Media player has to be launched manually after shutting down the MEDIA CENTER. Then I have to manually choose the DVD to play.

The ASP.NET account gets installed with .NET framework. It can be deleted.

You can change the autorun settings for a DVD to launch whatever you want.

Unfortunately the autorun for DVD does nothing to fix the problem of Media Center launching and Media player remaining unlaunched in my case as this is what happens no matter what I do. I have tried all the options available to me but it still does the Media Center launch and not the Media player launch.