Browser Closing on its own

I first noticed this yesterday. When I open up a link in Twitter, the page will display for a few seconds, then it closes and goes back to the Twitter app. I thought it had something to do with Tweetcaster but now it's happening even when I open the browser directly.  I downloaded Opera Mini just as a test and it works fine.  Any ideas?  TIA.

Try to hard reset.

I finally got this one figured out. It was closing on any page that contained Flash. I deleted the Flash app and reinstalled. No more problem.