How to restore my iPhone 3G?

So I pushed delete all content and settings on my jailbroken iPhone 3G, it is now showing the apple logo for about 3 hours (it flashes away quick every 20 minutes or so).Is this normal and if not, how do I fix it? My macbook pro does not find the iPhone, and my powerbutton is broken. Apple experts please help me?

Not normally. Try Hard Reset iPhone.
To do a Reset, press and hold the Home button and the Sleep/Wake or On/Off button simultaneously until you see the Apple logo and then release - ignoring the slide to turn off prompt when doing so.