welcome to the forum! Don't panic because even though it may look bad and you might think you have done serious damage pretty much everything can be fixed with a dfu+ restore.
Before you attempt this please tell us what you have done for the device to "crash" and hopefully we can advise you how to fix it with out doing a restore but if there is no other option then ..
Try this :
iClarified - iPhone - How to Put an iPhone Into DFU Mode then plug into itunes and you should be able to fix the device unless you spilt water on it or damaged it..