What does optimized charging means in sony ericsson K608i?

I have a problem with my phone, it doesnt start up after I charged it for two hours? It just shows the sony ericsson logo then it fades away. What could be the problem?Pls help to those who have knowledge in this.Thank you very much.|||Either your phone is not charging properly or there is a fault with the firmware. When you charge it does the charging screen show up? Normally a phone with a firmware problem will not show anything except for the infrared light flashing several times when the "ON" soft key is pressed. By the way just for extra knowledge, sony ericssons don't get viruses because of the operating system, higly unlightly because of the programming.