Is there a "hardware reset" for the Galaxy S? I have had my Samsung Galaxy S for less than a year, and never did anything like rooting it. Just normal use. 

About 60 minutes ago I opened from it's "sleep" state to check a web page and left it on my desk where it went to "sleep". 

Now about 10 minutes ago, I tried to open it again, but it's dead. Touching the screen doesn't bring up anything. I press and hold the power button which doesn't do anything. I don't remember the battery being low, but I plugged it in anyway. 

The recharge screen doesn't come up and it still won't start even with the power cord plugged in.

What can I do ? Is there some kind of hardware reset I can do ?
Sounds like the phone simply froze up. Try taking out the battery, putting it back in, and then press the Power button to start it.