I have a project (from a SVN repository), which ran yesterday when I start a new debug instance. It'd show me a form and let me do some stuff on it. Today, I tried to run a new debug instance again (the old one is closed/stopped). It's not showing me the form, although it seems like everything started and there were no errors shown.
I even tried to revert the SVN repository to the last version (the version I started with, which worked). Still, it's not showing me the form, so I was thinking perhaps I switched a setting or something?
I'm not too familiar with Visual Studio 2008 so I'd tought I ask here first.
If you are running Winforms there is an issue with the Form_Load EventHandler that if there is an error, it won't be thrown. I would put a breakpoint on the start of the Form_Load method and step through it making sure there are not any problems. See this SO Question.
If that doesn't work I would put your breakpoint in the Forms Constructor and step through your code to make sure that there are no problems with the InitializeComponent Method.
You also mention in your comment that your problem has to to with a Com Port. If you ran your program earlier and it hung or never really exited there still is a chance that an instance of your program is still running, you need to check your TaskManager. It can lock the port and prevent you from being able to open it( I have been there and done that ). I have had to Kill all instances of my program, and if that didn't work reboot the computer and the remote device.