Parallels Desktop 4.0 startup problem

Hey guys, I installed Parallels Desktop 4.0 on my Mac, I installed Windows xp Professional. It works perfectly, but every time I shut down my Mac after turning it on the next time there is always that white screen for a few seconds, if you don't press anything it runs the Windows xp black screen and asks to insert CD or something like that. I know that I have to press the alt button and select the Macintosh HD partition (only one).

My questions is: how can I make it so it runs automatically on the Macintosh Partition without having to select the partition? (how it normally started up)

I hope anyone knows how to do it, and hope it's very easy, because I'm not a real technician. I would appreciate your help, because I like my Mac to run smoothly.

Thanks,

Max

System Preferences, Startup Disk. Select your Macintosh HD as the default.

Regards.